51661523 has 4 divisors (see below), whose sum is σ = 51877920. Its totient is φ = 51445128.

The previous prime is 51661501. The next prime is 51661529. The reversal of 51661523 is 32516615.

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 51661523 - 2¹² = 51657427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51661529) 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, 107840 + ... + 108317.

It is an arithmetic number, because the mean of its divisors is an integer number (12969480).

Almost surely, 2^51661523 is an apocalyptic number.

51661523 is a deficient number, since it is larger than the sum of its proper divisors (216397).

51661523 is a wasteful number, since it uses less digits than its factorization.

51661523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216396.

The product of its digits is 5400, while the sum is 29.

The square root of 51661523 is about 7187.5950776320. The cubic root of 51661523 is about 372.4395001064.

The spelling of 51661523 in words is "fifty-one million, six hundred sixty-one thousand, five hundred twenty-three".