51551540 has 24 divisors (see below), whose sum is σ = 108442152. Its totient is φ = 20585600.

The previous prime is 51551537. The next prime is 51551557. The reversal of 51551540 is 4515515.

It can be written as a sum of positive squares in 4 ways, for example, as 20593444 + 30958096 = 4538^2 + 5564^2 .

It is a super-2 number, since 2×51551540² = 5315122552743200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12182 + ... + 15858.

It is an arithmetic number, because the mean of its divisors is an integer number (4518423).

Almost surely, 2^51551540 is an apocalyptic number.

It is an amenable number.

51551540 is an abundant number, since it is smaller than the sum of its proper divisors (56890612).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51551540 is a wasteful number, since it uses less digits than its factorization.

51551540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4387 (or 4385 counting only the distinct ones).

The product of its (nonzero) digits is 2500, while the sum is 26.

The square root of 51551540 is about 7179.9401111708. The cubic root of 51551540 is about 372.1750149615.

The spelling of 51551540 in words is "fifty-one million, five hundred fifty-one thousand, five hundred forty".