21813129949 has 8 divisors (see below), whose sum is σ = 24727435040. Its totient is φ = 19075449456.

The previous prime is 21813129907. The next prime is 21813129967. The reversal of 21813129949 is 94992131812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21813129949 - 2²⁷ = 21678912221 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 (21813129449) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44155887 + ... + 44156380.

It is an arithmetic number, because the mean of its divisors is an integer number (3090929380).

Almost surely, 2^21813129949 is an apocalyptic number.

It is an amenable number.

21813129949 is a deficient number, since it is larger than the sum of its proper divisors (2914305091).

21813129949 is a wasteful number, since it uses less digits than its factorization.

21813129949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88312299.

The product of its digits is 279936, while the sum is 49.

The spelling of 21813129949 in words is "twenty-one billion, eight hundred thirteen million, one hundred twenty-nine thousand, nine hundred forty-nine".