21261139199 has 32 divisors (see below), whose sum is σ = 23508144000. Its totient is φ = 19138904064.

The previous prime is 21261139183. The next prime is 21261139201. The reversal of 21261139199 is 99193116212.

It is a cyclic number.

It is not a de Polignac number, because 21261139199 - 2⁴ = 21261139183 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21261139399) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 41770157 + ... + 41770665.

It is an arithmetic number, because the mean of its divisors is an integer number (734629500).

Almost surely, 2^21261139199 is an apocalyptic number.

21261139199 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

21261139199 is a deficient number, since it is larger than the sum of its proper divisors (2247004801).

21261139199 is a wasteful number, since it uses less digits than its factorization.

21261139199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1187.

The product of its digits is 52488, while the sum is 44.

It can be divided in two parts, 2126113 and 9199, that added together give a palindrome (2135312).

The spelling of 21261139199 in words is "twenty-one billion, two hundred sixty-one million, one hundred thirty-nine thousand, one hundred ninety-nine".