51523320221 has 4 divisors (see below), whose sum is σ = 51527736000. Its totient is φ = 51518904444.

The previous prime is 51523320169. The next prime is 51523320239. The reversal of 51523320221 is 12202332515.

It is a happy number.

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 51523320221 - 2⁶ = 51523320157 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 (51523320421) 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, 2190341 + ... + 2213738.

It is an arithmetic number, because the mean of its divisors is an integer number (12881934000).

Almost surely, 2^51523320221 is an apocalyptic number.

It is an amenable number.

51523320221 is a deficient number, since it is larger than the sum of its proper divisors (4415779).

51523320221 is a wasteful number, since it uses less digits than its factorization.

51523320221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4415778.

The product of its (nonzero) digits is 3600, while the sum is 26.

Adding to 51523320221 its reverse (12202332515), we get a palindrome (63725652736).

The spelling of 51523320221 in words is "fifty-one billion, five hundred twenty-three million, three hundred twenty thousand, two hundred twenty-one".