21015521454 has 32 divisors (see below), whose sum is σ = 43081635744. Its totient is φ = 6830277120.

The previous prime is 21015521453. The next prime is 21015521503. The reversal of 21015521454 is 45412551012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21015521453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 406872 + ... + 455604.

It is an arithmetic number, because the mean of its divisors is an integer number (1346301117).

Almost surely, 2^21015521454 is an apocalyptic number.

21015521454 is an abundant number, since it is smaller than the sum of its proper divisors (22066114290).

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

21015521454 is a wasteful number, since it uses less digits than its factorization.

21015521454 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50532.

The product of its (nonzero) digits is 8000, while the sum is 30.

The spelling of 21015521454 in words is "twenty-one billion, fifteen million, five hundred twenty-one thousand, four hundred fifty-four".