111949798921 has 27 divisors (see below), whose sum is σ = 117163513831. Its totient is φ = 106966764944.

The previous prime is 111949798871. The next prime is 111949798931. The reversal of 111949798921 is 129897949111.

The square root of 111949798921 is 334589.

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., 80704287225 + 31245511696 = 284085^2 + 176764^2 .

It is not a de Polignac number, because 111949798921 - 2³³ = 103359864329 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 111949798921.

It is not an unprimeable number, because it can be changed into a prime (111949798931) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1046259750 + ... + 1046259856.

Almost surely, 2^111949798921 is an apocalyptic number.

111949798921 is the 334589-th square number.

111949798921 is the 167295-th centered octagonal number.

It is an amenable number.

111949798921 is a deficient number, since it is larger than the sum of its proper divisors (5213714910).

111949798921 is an frugal number, since it uses more digits than its factorization.

111949798921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 438 (or 219 counting only the distinct ones).

The product of its digits is 2939328, while the sum is 61.

The spelling of 111949798921 in words is "one hundred eleven billion, nine hundred forty-nine million, seven hundred ninety-eight thousand, nine hundred twenty-one".