61631921 has 8 divisors (see below), whose sum is σ = 66532200. Its totient is φ = 56754432.

The previous prime is 61631903. The next prime is 61631939. The reversal of 61631921 is 12913616.

It is an interprime number because it is at equal distance from previous prime (61631903) and next prime (61631939).

It can be written as a sum of positive squares in 4 ways, for example, as 5456896 + 56175025 = 2336^2 + 7495^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 61631921 - 2²² = 57437617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61631971) 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, 155 + ... + 11103.

It is an arithmetic number, because the mean of its divisors is an integer number (8316525).

Almost surely, 2^61631921 is an apocalyptic number.

It is an amenable number.

61631921 is a deficient number, since it is larger than the sum of its proper divisors (4900279).

61631921 is a wasteful number, since it uses less digits than its factorization.

61631921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11395.

The product of its digits is 1944, while the sum is 29.

The square root of 61631921 is about 7850.6000407612. The cubic root of 61631921 is about 395.0043710460.

The spelling of 61631921 in words is "sixty-one million, six hundred thirty-one thousand, nine hundred twenty-one".