51860821 has 4 divisors (see below), whose sum is σ = 51948000. Its totient is φ = 51773644.

The previous prime is 51860819. The next prime is 51860827. The reversal of 51860821 is 12806815.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 51860821 - 2¹ = 51860819 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51860827) 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, 42691 + ... + 43888.

It is an arithmetic number, because the mean of its divisors is an integer number (12987000).

Almost surely, 2^51860821 is an apocalyptic number.

It is an amenable number.

51860821 is a deficient number, since it is larger than the sum of its proper divisors (87179).

51860821 is an equidigital number, since it uses as much as digits as its factorization.

51860821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87178.

The product of its (nonzero) digits is 3840, while the sum is 31.

The square root of 51860821 is about 7201.4457576240. The cubic root of 51860821 is about 372.9178135451.

The spelling of 51860821 in words is "fifty-one million, eight hundred sixty thousand, eight hundred twenty-one".