51301821 has 4 divisors (see below), whose sum is σ = 68402432. Its totient is φ = 34201212.

The previous prime is 51301781. The next prime is 51301823. The reversal of 51301821 is 12810315.

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 not a de Polignac number, because 51301821 - 2⁷ = 51301693 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 (51301823) 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, 8550301 + ... + 8550306.

It is an arithmetic number, because the mean of its divisors is an integer number (17100608).

Almost surely, 2^51301821 is an apocalyptic number.

It is an amenable number.

51301821 is a deficient number, since it is larger than the sum of its proper divisors (17100611).

51301821 is a wasteful number, since it uses less digits than its factorization.

51301821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17100610.

The product of its (nonzero) digits is 240, while the sum is 21.

The square root of 51301821 is about 7162.5289528211. The cubic root of 51301821 is about 371.5730953711.

The spelling of 51301821 in words is "fifty-one million, three hundred one thousand, eight hundred twenty-one".