221138943257 has 4 divisors (see below), whose sum is σ = 222547471716. Its totient is φ = 219730414800.

The previous prime is 221138943209. The next prime is 221138943323. The reversal of 221138943257 is 752349831122.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 109732525081 + 111406418176 = 331259^2 + 333776^2 .

It is a cyclic number.

It is not a de Polignac number, because 221138943257 - 2³² = 216843975961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221138948257) 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, 704263994 + ... + 704264307.

It is an arithmetic number, because the mean of its divisors is an integer number (55636867929).

Almost surely, 2^221138943257 is an apocalyptic number.

It is an amenable number.

221138943257 is a deficient number, since it is larger than the sum of its proper divisors (1408528459).

221138943257 is a wasteful number, since it uses less digits than its factorization.

221138943257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1408528458.

The product of its digits is 725760, while the sum is 47.

The spelling of 221138943257 in words is "two hundred twenty-one billion, one hundred thirty-eight million, nine hundred forty-three thousand, two hundred fifty-seven".