51521399 has 2 divisors, whose sum is σ = 51521400. Its totient is φ = 51521398.

The previous prime is 51521389. The next prime is 51521401. The reversal of 51521399 is 99312515.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 51521399 - 2²⁰ = 50472823 is a prime.

Together with 51521401, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51521329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25760699 + 25760700.

It is an arithmetic number, because the mean of its divisors is an integer number (25760700).

Almost surely, 2^51521399 is an apocalyptic number.

51521399 is a deficient number, since it is larger than the sum of its proper divisors (1).

51521399 is an equidigital number, since it uses as much as digits as its factorization.

51521399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12150, while the sum is 35.

The square root of 51521399 is about 7177.8408313364. The cubic root of 51521399 is about 372.1024667629.

The spelling of 51521399 in words is "fifty-one million, five hundred twenty-one thousand, three hundred ninety-nine".