51661530 has 32 divisors (see below), whose sum is σ = 137764800. Its totient is φ = 13776336.

The previous prime is 51661529. The next prime is 51661537. The reversal of 51661530 is 3516615.

It is a happy number.

51661530 is a `hidden beast` number, since 5 + 16 + 615 + 30 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 51661494 and 51661503.

It is not an unprimeable number, because it can be changed into a prime (51661537) 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, 95400 + ... + 95939.

It is an arithmetic number, because the mean of its divisors is an integer number (4305150).

Almost surely, 2^51661530 is an apocalyptic number.

51661530 is an abundant number, since it is smaller than the sum of its proper divisors (86103270).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51661530 is a wasteful number, since it uses less digits than its factorization.

51661530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191355 (or 191349 counting only the distinct ones).

The product of its (nonzero) digits is 2700, while the sum is 27.

The square root of 51661530 is about 7187.5955645821. The cubic root of 51661530 is about 372.4395169279.

The spelling of 51661530 in words is "fifty-one million, six hundred sixty-one thousand, five hundred thirty".