51951639 has 4 divisors (see below), whose sum is σ = 69268856. Its totient is φ = 34634424.

The previous prime is 51951619. The next prime is 51951659. The reversal of 51951639 is 93615915.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (51951619) and next prime (51951659).

It is not a de Polignac number, because 51951639 - 2⁷ = 51951511 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51951597 and 51951606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51951619) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8658604 + ... + 8658609.

It is an arithmetic number, because the mean of its divisors is an integer number (17317214).

Almost surely, 2^51951639 is an apocalyptic number.

51951639 is a deficient number, since it is larger than the sum of its proper divisors (17317217).

51951639 is a wasteful number, since it uses less digits than its factorization.

51951639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17317216.

The product of its digits is 36450, while the sum is 39.

The square root of 51951639 is about 7207.7485388990. The cubic root of 51951639 is about 373.1353695538.

The spelling of 51951639 in words is "fifty-one million, nine hundred fifty-one thousand, six hundred thirty-nine".