21158117526 has 64 divisors (see below), whose sum is σ = 52401259008. Its totient is φ = 5545905408.

The previous prime is 21158117521. The next prime is 21158117543. The reversal of 21158117526 is 62571185112.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21158117521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 29871 + ... + 207866.

It is an arithmetic number, because the mean of its divisors is an integer number (818769672).

Almost surely, 2^21158117526 is an apocalyptic number.

21158117526 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21158117526 is an abundant number, since it is smaller than the sum of its proper divisors (31243141482).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21158117526 is a wasteful number, since it uses less digits than its factorization.

21158117526 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 237925.

The product of its digits is 33600, while the sum is 39.

The spelling of 21158117526 in words is "twenty-one billion, one hundred fifty-eight million, one hundred seventeen thousand, five hundred twenty-six".