51720499 has 2 divisors, whose sum is σ = 51720500. Its totient is φ = 51720498.

The previous prime is 51720463. The next prime is 51720509. The reversal of 51720499 is 99402715.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 51720499 - 2¹¹ = 51718451 is a prime.

It is not a weakly prime, because it can be changed into another prime (51720419) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25860249 + 25860250.

It is an arithmetic number, because the mean of its divisors is an integer number (25860250).

Almost surely, 2^51720499 is an apocalyptic number.

51720499 is a deficient number, since it is larger than the sum of its proper divisors (1).

51720499 is an equidigital number, since it uses as much as digits as its factorization.

51720499 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22680, while the sum is 37.

The square root of 51720499 is about 7191.6965314173. The cubic root of 51720499 is about 372.5811699455.

The spelling of 51720499 in words is "fifty-one million, seven hundred twenty thousand, four hundred ninety-nine".