61722121620 has 24 divisors (see below), whose sum is σ = 172821940704. Its totient is φ = 16459232416.

The previous prime is 61722121603. The next prime is 61722121621. The reversal of 61722121620 is 2612122716.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61722121621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 514350954 + ... + 514351073.

It is an arithmetic number, because the mean of its divisors is an integer number (7200914196).

Almost surely, 2^61722121620 is an apocalyptic number.

61722121620 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

61722121620 is an abundant number, since it is smaller than the sum of its proper divisors (111099819084).

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

61722121620 is a wasteful number, since it uses less digits than its factorization.

61722121620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1028702039 (or 1028702037 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 30.

The spelling of 61722121620 in words is "sixty-one billion, seven hundred twenty-two million, one hundred twenty-one thousand, six hundred twenty".