521551421 has 4 divisors (see below), whose sum is σ = 521647392. Its totient is φ = 521455452.

The previous prime is 521551417. The next prime is 521551423. The reversal of 521551421 is 124155125.

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 521551421 - 2² = 521551417 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 (521551423) 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, 39311 + ... + 50876.

It is an arithmetic number, because the mean of its divisors is an integer number (130411848).

Almost surely, 2^521551421 is an apocalyptic number.

It is an amenable number.

521551421 is a deficient number, since it is larger than the sum of its proper divisors (95971).

521551421 is an equidigital number, since it uses as much as digits as its factorization.

521551421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95970.

The product of its digits is 2000, while the sum is 26.

The square root of 521551421 is about 22837.5003229338. The cubic root of 521551421 is about 804.9440805774.

The spelling of 521551421 in words is "five hundred twenty-one million, five hundred fifty-one thousand, four hundred twenty-one".