61617920 has 216 divisors, whose sum is σ = 189895776. Its totient is φ = 18653184.

The previous prime is 61617917. The next prime is 61617923. The reversal of 61617920 is 2971616.

It is a happy number.

61617920 is nontrivially palindromic in base 15.

It is an interprime number because it is at equal distance from previous prime (61617917) and next prime (61617923).

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61617923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2679029 + ... + 2679051.

Almost surely, 2^61617920 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61617920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94947888).

61617920 is an abundant number, since it is smaller than the sum of its proper divisors (128277856).

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

61617920 is a wasteful number, since it uses less digits than its factorization.

61617920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87 (or 50 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 61617920 is about 7849.7082748342. The cubic root of 61617920 is about 394.9744575696.

The spelling of 61617920 in words is "sixty-one million, six hundred seventeen thousand, nine hundred twenty".