61657791 has 24 divisors (see below), whose sum is σ = 91915776. Its totient is φ = 36709920.

The previous prime is 61657789. The next prime is 61657801. The reversal of 61657791 is 19775616.

It is not a de Polignac number, because 61657791 - 2¹ = 61657789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61657721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13756 + ... + 17678.

It is an arithmetic number, because the mean of its divisors is an integer number (3829824).

Almost surely, 2^61657791 is an apocalyptic number.

61657791 is a deficient number, since it is larger than the sum of its proper divisors (30257985).

61657791 is a wasteful number, since it uses less digits than its factorization.

61657791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3983 (or 3970 counting only the distinct ones).

The product of its digits is 79380, while the sum is 42.

The square root of 61657791 is about 7852.2475126552. The cubic root of 61657791 is about 395.0596310123.

The spelling of 61657791 in words is "sixty-one million, six hundred fifty-seven thousand, seven hundred ninety-one".