21158133231 has 4 divisors (see below), whose sum is σ = 28210844312. Its totient is φ = 14105422152.

The previous prime is 21158133181. The next prime is 21158133239. The reversal of 21158133231 is 13233185112.

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

It is not a de Polignac number, because 21158133231 - 2⁹ = 21158132719 is a prime.

It is a super-2 number, since 2×21158133231² (a number of 21 digits) 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 (21158133239) 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, 3526355536 + ... + 3526355541.

It is an arithmetic number, because the mean of its divisors is an integer number (7052711078).

Almost surely, 2^21158133231 is an apocalyptic number.

21158133231 is a deficient number, since it is larger than the sum of its proper divisors (7052711081).

21158133231 is an equidigital number, since it uses as much as digits as its factorization.

21158133231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7052711080.

The product of its digits is 4320, while the sum is 30.

The spelling of 21158133231 in words is "twenty-one billion, one hundred fifty-eight million, one hundred thirty-three thousand, two hundred thirty-one".