21158382121 has 32 divisors (see below), whose sum is σ = 24539189760. Its totient is φ = 18115209216.

The previous prime is 21158382109. The next prime is 21158382143. The reversal of 21158382121 is 12128385112.

It is not a de Polignac number, because 21158382121 - 2¹¹ = 21158380073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21158382101) 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, 791445 + ... + 817741.

It is an arithmetic number, because the mean of its divisors is an integer number (766849680).

Almost surely, 2^21158382121 is an apocalyptic number.

It is an amenable number.

21158382121 is a deficient number, since it is larger than the sum of its proper divisors (3380807639).

21158382121 is a wasteful number, since it uses less digits than its factorization.

21158382121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26433.

The product of its digits is 7680, while the sum is 34.

The spelling of 21158382121 in words is "twenty-one billion, one hundred fifty-eight million, three hundred eighty-two thousand, one hundred twenty-one".