61399131 has 4 divisors (see below), whose sum is σ = 81865512. Its totient is φ = 40932752.

The previous prime is 61399111. The next prime is 61399133. The reversal of 61399131 is 13199316.

It is a happy number.

61399131 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 61399131 - 2⁶ = 61399067 is a prime.

It is a super-2 number, since 2×61399131² = 7539706575110322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 61399092 and 61399101.

It is not an unprimeable number, because it can be changed into a prime (61399133) 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 3 ways as a sum of consecutive naturals, for example, 10233186 + ... + 10233191.

It is an arithmetic number, because the mean of its divisors is an integer number (20466378).

Almost surely, 2^61399131 is an apocalyptic number.

61399131 is a deficient number, since it is larger than the sum of its proper divisors (20466381).

61399131 is a wasteful number, since it uses less digits than its factorization.

61399131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20466380.

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

The square root of 61399131 is about 7835.7597589513. The cubic root of 61399131 is about 394.5064197593.

The spelling of 61399131 in words is "sixty-one million, three hundred ninety-nine thousand, one hundred thirty-one".