21122515554 has 32 divisors (see below), whose sum is σ = 49265347200. Its totient is φ = 6035003856.

The previous prime is 21122515553. The next prime is 21122515571. The reversal of 21122515554 is 45551522112.

It is not an unprimeable number, because it can be changed into a prime (21122515553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5129749 + ... + 5133864.

It is an arithmetic number, because the mean of its divisors is an integer number (1539542100).

Almost surely, 2^21122515554 is an apocalyptic number.

21122515554 is an abundant number, since it is smaller than the sum of its proper divisors (28142831646).

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

21122515554 is a wasteful number, since it uses less digits than its factorization.

21122515554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10263639 (or 10263625 counting only the distinct ones).

The product of its digits is 20000, while the sum is 33.

The spelling of 21122515554 in words is "twenty-one billion, one hundred twenty-two million, five hundred fifteen thousand, five hundred fifty-four".