228775879864921 has 9 divisors (see below), whose sum is σ = 231566695350879. Its totient is φ = 226018303685136.

The previous prime is 228775879864891. The next prime is 228775879864937. The reversal of 228775879864921 is 129468978577822.

The square root of 228775879864921 is 15125339.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 173952754483225 + 54823125381696 = 13189115^2 + 7404264^2 .

It is not a de Polignac number, because 228775879864921 - 2⁴³ = 219979786842713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (228775879864421) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1255312021 + ... + 1255494253.

Almost surely, 2^{228775879864921} is an apocalyptic number.

228775879864921 is the 15125339-th square number.

228775879864921 is the 7562670-th centered octagonal number.

It is an amenable number.

228775879864921 is a deficient number, since it is larger than the sum of its proper divisors (2790815485958).

228775879864921 is an frugal number, since it uses more digits than its factorization.

228775879864921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 364632 (or 182316 counting only the distinct ones).

The product of its digits is 13655900160, while the sum is 85.

The spelling of 228775879864921 in words is "two hundred twenty-eight trillion, seven hundred seventy-five billion, eight hundred seventy-nine million, eight hundred sixty-four thousand, nine hundred twenty-one".