53515661 has 4 divisors (see below), whose sum is σ = 54160512. Its totient is φ = 52870812.

The previous prime is 53515639. The next prime is 53515663. The reversal of 53515661 is 16651535.

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.

It is a cyclic number.

It is not a de Polignac number, because 53515661 - 2¹⁸ = 53253517 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 (53515663) 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, 322301 + ... + 322466.

It is an arithmetic number, because the mean of its divisors is an integer number (13540128).

Almost surely, 2^53515661 is an apocalyptic number.

It is an amenable number.

53515661 is a deficient number, since it is larger than the sum of its proper divisors (644851).

53515661 is an equidigital number, since it uses as much as digits as its factorization.

53515661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 644850.

The product of its digits is 13500, while the sum is 32.

The square root of 53515661 is about 7315.4399047494. The cubic root of 53515661 is about 376.8428659369.

The spelling of 53515661 in words is "fifty-three million, five hundred fifteen thousand, six hundred sixty-one".