51687497 has 8 divisors (see below), whose sum is σ = 55129896. Its totient is φ = 48289792.

The previous prime is 51687487. The next prime is 51687521. The reversal of 51687497 is 79478615.

It can be written as a sum of positive squares in 4 ways, for example, as 29822521 + 21864976 = 5461^2 + 4676^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 51687497 - 2⁸ = 51687241 is a prime.

It is a super-2 number, since 2×51687497² = 5343194692250018, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (51687487) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8768 + ... + 13425.

It is an arithmetic number, because the mean of its divisors is an integer number (6891237).

Almost surely, 2^51687497 is an apocalyptic number.

It is an amenable number.

51687497 is a deficient number, since it is larger than the sum of its proper divisors (3442399).

51687497 is a wasteful number, since it uses less digits than its factorization.

51687497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22347.

The product of its digits is 423360, while the sum is 47.

The square root of 51687497 is about 7189.4017136338. The cubic root of 51687497 is about 372.5019071115.

The spelling of 51687497 in words is "fifty-one million, six hundred eighty-seven thousand, four hundred ninety-seven".