51507421 has 16 divisors (see below), whose sum is σ = 60594688. Its totient is φ = 42865200.

The previous prime is 51507403. The next prime is 51507427. The reversal of 51507421 is 12470515.

It is not a de Polignac number, because 51507421 - 2¹⁷ = 51376349 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51507427) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 63106 + ... + 63916.

It is an arithmetic number, because the mean of its divisors is an integer number (3787168).

Almost surely, 2^51507421 is an apocalyptic number.

It is an amenable number.

51507421 is a deficient number, since it is larger than the sum of its proper divisors (9087267).

51507421 is a wasteful number, since it uses less digits than its factorization.

51507421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1072.

The product of its (nonzero) digits is 1400, while the sum is 25.

The square root of 51507421 is about 7176.8670741487. The cubic root of 51507421 is about 372.0688126643.

Adding to 51507421 its reverse (12470515), we get a palindrome (63977936).

The spelling of 51507421 in words is "fifty-one million, five hundred seven thousand, four hundred twenty-one".