111661621 has 4 divisors (see below), whose sum is σ = 111825792. Its totient is φ = 111497452.

The previous prime is 111661609. The next prime is 111661637. The reversal of 111661621 is 126166111.

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 111661621 - 2⁷ = 111661493 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 (111661601) 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, 81061 + ... + 82426.

It is an arithmetic number, because the mean of its divisors is an integer number (27956448).

Almost surely, 2^111661621 is an apocalyptic number.

It is an amenable number.

111661621 is a deficient number, since it is larger than the sum of its proper divisors (164171).

111661621 is an equidigital number, since it uses as much as digits as its factorization.

111661621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164170.

The product of its digits is 432, while the sum is 25.

The square root of 111661621 is about 10567.0062458579. The cubic root of 111661621 is about 481.5425217479.

The spelling of 111661621 in words is "one hundred eleven million, six hundred sixty-one thousand, six hundred twenty-one".