51720487 has 16 divisors (see below), whose sum is σ = 65380672. Its totient is φ = 39813120.

The previous prime is 51720463. The next prime is 51720499. The reversal of 51720487 is 78402715.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 51720487 - 2⁷ = 51720359 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51720407) 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, 4314 + ... + 11047.

It is an arithmetic number, because the mean of its divisors is an integer number (4086292).

Almost surely, 2^51720487 is an apocalyptic number.

51720487 is a deficient number, since it is larger than the sum of its proper divisors (13660185).

51720487 is a wasteful number, since it uses less digits than its factorization.

51720487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15418.

The product of its (nonzero) digits is 15680, while the sum is 34.

The square root of 51720487 is about 7191.6956971218. The cubic root of 51720487 is about 372.5811411305.

The spelling of 51720487 in words is "fifty-one million, seven hundred twenty thousand, four hundred eighty-seven".