61681757 has 4 divisors (see below), whose sum is σ = 61697856. Its totient is φ = 61665660.

The previous prime is 61681751. The next prime is 61681777. The reversal of 61681757 is 75718616.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61681757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61681751) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1382 + ... + 11192.

It is an arithmetic number, because the mean of its divisors is an integer number (15424464).

Almost surely, 2^61681757 is an apocalyptic number.

It is an amenable number.

61681757 is a deficient number, since it is larger than the sum of its proper divisors (16099).

61681757 is an equidigital number, since it uses as much as digits as its factorization.

61681757 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16098.

The product of its digits is 70560, while the sum is 41.

The square root of 61681757 is about 7853.7734242847. The cubic root of 61681757 is about 395.1108101227.

The spelling of 61681757 in words is "sixty-one million, six hundred eighty-one thousand, seven hundred fifty-seven".