61391931 has 8 divisors (see below), whose sum is σ = 81951744. Its totient is φ = 40880040.

The previous prime is 61391921. The next prime is 61391951. The reversal of 61391931 is 13919316.

It is a happy number.

61391931 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 61391931 - 2¹⁵ = 61359163 is a prime.

It is a super-2 number, since 2×61391931² = 7537938383817522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 61391892 and 61391901.

It is not an unprimeable number, because it can be changed into a prime (61391921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8875 + ... + 14196.

It is an arithmetic number, because the mean of its divisors is an integer number (10243968).

Almost surely, 2^61391931 is an apocalyptic number.

61391931 is a deficient number, since it is larger than the sum of its proper divisors (20559813).

61391931 is a wasteful number, since it uses less digits than its factorization.

61391931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23961.

The product of its digits is 4374, while the sum is 33.

The square root of 61391931 is about 7835.3003133256. The cubic root of 61391931 is about 394.4909984918.

The spelling of 61391931 in words is "sixty-one million, three hundred ninety-one thousand, nine hundred thirty-one".