61631920 has 80 divisors (see below), whose sum is σ = 165043008. Its totient is φ = 20966400.

The previous prime is 61631903. The next prime is 61631939. The reversal of 61631920 is 2913616.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (28).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87570 + ... + 88270.

Almost surely, 2^61631920 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 61631920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82521504).

61631920 is an abundant number, since it is smaller than the sum of its proper divisors (103411088).

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

61631920 is a wasteful number, since it uses less digits than its factorization.

61631920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 878 (or 872 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 61631920 is about 7850.5999770718. The cubic root of 61631920 is about 395.0043689096.

The spelling of 61631920 in words is "sixty-one million, six hundred thirty-one thousand, nine hundred twenty".