21351552240 has 40 divisors (see below), whose sum is σ = 66189812688. Its totient is φ = 5693747200.

The previous prime is 21351552239. The next prime is 21351552263. The reversal of 21351552240 is 4225515312.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 21351552198 and 21351552207.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44482161 + ... + 44482640.

Almost surely, 2^21351552240 is an apocalyptic number.

21351552240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21351552240 is an abundant number, since it is smaller than the sum of its proper divisors (44838260448).

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

21351552240 is a wasteful number, since it uses less digits than its factorization.

21351552240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88964817 (or 88964811 counting only the distinct ones).

The product of its (nonzero) digits is 12000, while the sum is 30.

The spelling of 21351552240 in words is "twenty-one billion, three hundred fifty-one million, five hundred fifty-two thousand, two hundred forty".