21161199 has 4 divisors (see below), whose sum is σ = 28214936. Its totient is φ = 14107464.

The previous prime is 21161191. The next prime is 21161227. The reversal of 21161199 is 99116112.

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

It is not a de Polignac number, because 21161199 - 2³ = 21161191 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 (21161191) 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, 3526864 + ... + 3526869.

It is an arithmetic number, because the mean of its divisors is an integer number (7053734).

Almost surely, 2^21161199 is an apocalyptic number.

21161199 is a deficient number, since it is larger than the sum of its proper divisors (7053737).

21161199 is an equidigital number, since it uses as much as digits as its factorization.

21161199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7053736.

The product of its digits is 972, while the sum is 30.

The square root of 21161199 is about 4600.1303242408. The cubic root of 21161199 is about 276.5965488993.

The spelling of 21161199 in words is "twenty-one million, one hundred sixty-one thousand, one hundred ninety-nine".