21357553540 has 48 divisors (see below), whose sum is σ = 47426932224. Its totient is φ = 8065785600.

The previous prime is 21357553493. The next prime is 21357553559. The reversal of 21357553540 is 4535575312.

It is a happy number.

It is a super-2 number, since 2×21357553540² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21357553493 and 21357553502.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 394674 + ... + 445513.

It is an arithmetic number, because the mean of its divisors is an integer number (988061088).

Almost surely, 2^21357553540 is an apocalyptic number.

21357553540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21357553540 is an abundant number, since it is smaller than the sum of its proper divisors (26069378684).

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

21357553540 is a wasteful number, since it uses less digits than its factorization.

21357553540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 840268 (or 840266 counting only the distinct ones).

The product of its (nonzero) digits is 315000, while the sum is 40.

The spelling of 21357553540 in words is "twenty-one billion, three hundred fifty-seven million, five hundred fifty-three thousand, five hundred forty".