61657521 has 16 divisors (see below), whose sum is σ = 87591744. Its totient is φ = 38444544.

The previous prime is 61657499. The next prime is 61657523. The reversal of 61657521 is 12575616.

It is not a de Polignac number, because 61657521 - 2¹⁵ = 61624753 is a prime.

It is not an unprimeable number, because it can be changed into a prime (61657523) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4605 + ... + 12021.

It is an arithmetic number, because the mean of its divisors is an integer number (5474484).

Almost surely, 2^61657521 is an apocalyptic number.

It is an amenable number.

61657521 is a deficient number, since it is larger than the sum of its proper divisors (25934223).

61657521 is a wasteful number, since it uses less digits than its factorization.

61657521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7600.

The product of its digits is 12600, while the sum is 33.

The square root of 61657521 is about 7852.2303201065. The cubic root of 61657521 is about 395.0590543550.

The spelling of 61657521 in words is "sixty-one million, six hundred fifty-seven thousand, five hundred twenty-one".