21253563560 has 64 divisors (see below), whose sum is σ = 49973932800. Its totient is φ = 8127012096.

The previous prime is 21253563547. The next prime is 21253563581. The reversal of 21253563560 is 6536535212.

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, 50615 + ... + 212294.

It is an arithmetic number, because the mean of its divisors is an integer number (780842700).

Almost surely, 2^21253563560 is an apocalyptic number.

21253563560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21253563560 is an abundant number, since it is smaller than the sum of its proper divisors (28720369240).

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

21253563560 is a wasteful number, since it uses less digits than its factorization.

21253563560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 263010 (or 263006 counting only the distinct ones).

The product of its (nonzero) digits is 162000, while the sum is 38.

The spelling of 21253563560 in words is "twenty-one billion, two hundred fifty-three million, five hundred sixty-three thousand, five hundred sixty".