21354135520 has 48 divisors (see below), whose sum is σ = 50920673328. Its totient is φ = 8461818880.

The previous prime is 21354135499. The next prime is 21354135521. The reversal of 21354135520 is 2553145312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21354135521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 606541 + ... + 640780.

It is an arithmetic number, because the mean of its divisors is an integer number (1060847361).

Almost surely, 2^21354135520 is an apocalyptic number.

21354135520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21354135520 is an abundant number, since it is smaller than the sum of its proper divisors (29566537808).

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

21354135520 is a wasteful number, since it uses less digits than its factorization.

21354135520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1247443 (or 1247435 counting only the distinct ones).

The product of its (nonzero) digits is 18000, while the sum is 31.

The spelling of 21354135520 in words is "twenty-one billion, three hundred fifty-four million, one hundred thirty-five thousand, five hundred twenty".