61531620 has 48 divisors (see below), whose sum is σ = 178234560. Its totient is φ = 15842176.

The previous prime is 61531607. The next prime is 61531637. The reversal of 61531620 is 2613516.

It is a super-2 number, since 2×61531620² = 7572280519648800, which contains 22 as substring.

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, 15942 + ... + 19421.

It is an arithmetic number, because the mean of its divisors is an integer number (3713220).

Almost surely, 2^61531620 is an apocalyptic number.

61531620 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

61531620 is an abundant number, since it is smaller than the sum of its proper divisors (116702940).

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

61531620 is a wasteful number, since it uses less digits than its factorization.

61531620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35404 (or 35402 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 61531620 is about 7844.2093291803. The cubic root of 61531620 is about 394.7899754068.

The spelling of 61531620 in words is "sixty-one million, five hundred thirty-one thousand, six hundred twenty".