21121199 has 16 divisors (see below), whose sum is σ = 24827904. Its totient is φ = 17767200.

The previous prime is 21121187. The next prime is 21121201. The reversal of 21121199 is 99112112.

It is not a de Polignac number, because 21121199 - 2¹⁶ = 21055663 is a prime.

It is a super-2 number, since 2×21121199² = 892210094395202, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6497 + ... + 9189.

It is an arithmetic number, because the mean of its divisors is an integer number (1551744).

Almost surely, 2^21121199 is an apocalyptic number.

21121199 is a deficient number, since it is larger than the sum of its proper divisors (3706705).

21121199 is a wasteful number, since it uses less digits than its factorization.

21121199 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2758.

The product of its digits is 324, while the sum is 26.

The square root of 21121199 is about 4595.7805648225. The cubic root of 21121199 is about 276.4221599079.

The spelling of 21121199 in words is "twenty-one million, one hundred twenty-one thousand, one hundred ninety-nine".