51720147 has 32 divisors (see below), whose sum is σ = 82656000. Its totient is φ = 31855680.

The previous prime is 51720143. The next prime is 51720157. The reversal of 51720147 is 74102715.

51720147 is a `hidden beast` number, since 517 + 2 + 0 + 147 = 666.

It is not a de Polignac number, because 51720147 - 2² = 51720143 is a prime.

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

It is a self number, because there is not a number n which added to its sum of digits gives 51720147.

It is not an unprimeable number, because it can be changed into a prime (51720143) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19804 + ... + 22262.

It is an arithmetic number, because the mean of its divisors is an integer number (2583000).

Almost surely, 2^51720147 is an apocalyptic number.

51720147 is a gapful number since it is divisible by the number (57) formed by its first and last digit.

51720147 is a deficient number, since it is larger than the sum of its proper divisors (30935853).

51720147 is a wasteful number, since it uses less digits than its factorization.

51720147 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2528 (or 2522 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 27.

The square root of 51720147 is about 7191.6720587079. The cubic root of 51720147 is about 372.5803247044.

The spelling of 51720147 in words is "fifty-one million, seven hundred twenty thousand, one hundred forty-seven".