51251989 has 4 divisors (see below), whose sum is σ = 51973920. Its totient is φ = 50530060.

The previous prime is 51251951. The next prime is 51252013. The reversal of 51251989 is 98915215.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 51251989 - 2⁷ = 51251861 is a prime.

It is a super-2 number, since 2×51251989² = 5253532752912242, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51251939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 360859 + ... + 361000.

It is an arithmetic number, because the mean of its divisors is an integer number (12993480).

Almost surely, 2^51251989 is an apocalyptic number.

It is an amenable number.

51251989 is a deficient number, since it is larger than the sum of its proper divisors (721931).

51251989 is an equidigital number, since it uses as much as digits as its factorization.

51251989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 721930.

The product of its digits is 32400, while the sum is 40.

The square root of 51251989 is about 7159.0494480762. The cubic root of 51251989 is about 371.4527472782.

The spelling of 51251989 in words is "fifty-one million, two hundred fifty-one thousand, nine hundred eighty-nine".