61729920 has 192 divisors, whose sum is σ = 243771840. Its totient is φ = 14100480.

The previous prime is 61729909. The next prime is 61729931. The reversal of 61729920 is 2992716.

61729920 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (61729909) and next prime (61729931).

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 39555 + ... + 41085.

It is an arithmetic number, because the mean of its divisors is an integer number (1269645).

Almost surely, 2^61729920 is an apocalyptic number.

61729920 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61729920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121885920).

61729920 is an abundant number, since it is smaller than the sum of its proper divisors (182041920).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61729920 is a wasteful number, since it uses less digits than its factorization.

61729920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1563 (or 1548 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 36.

The square root of 61729920 is about 7856.8390590619. The cubic root of 61729920 is about 395.2136215644.

The spelling of 61729920 in words is "sixty-one million, seven hundred twenty-nine thousand, nine hundred twenty".