51402540 has 48 divisors (see below), whose sum is σ = 164489472. Its totient is φ = 11749056.

The previous prime is 51402521. The next prime is 51402551. The reversal of 51402540 is 4520415.

It is a super-2 number, since 2×51402540² = 5284442236903200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 60774 + ... + 61613.

It is an arithmetic number, because the mean of its divisors is an integer number (3426864).

Almost surely, 2^51402540 is an apocalyptic number.

It is an amenable number.

51402540 is an abundant number, since it is smaller than the sum of its proper divisors (113086932).

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

51402540 is a wasteful number, since it uses less digits than its factorization.

51402540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122406 (or 122404 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 21.

The square root of 51402540 is about 7169.5564716376. The cubic root of 51402540 is about 371.8161017283.

Adding to 51402540 its reverse (4520415), we get a palindrome (55922955).

The spelling of 51402540 in words is "fifty-one million, four hundred two thousand, five hundred forty".