21553065420 has 48 divisors (see below), whose sum is σ = 61632603648. Its totient is φ = 5625196480.

The previous prime is 21553065367. The next prime is 21553065439. The reversal of 21553065420 is 2456035512.

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, 3818646 + ... + 3824285.

It is an arithmetic number, because the mean of its divisors is an integer number (1284012576).

Almost surely, 2^21553065420 is an apocalyptic number.

21553065420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21553065420 is an abundant number, since it is smaller than the sum of its proper divisors (40079538228).

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

21553065420 is a wasteful number, since it uses less digits than its factorization.

21553065420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7642990 (or 7642988 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 33.

The spelling of 21553065420 in words is "twenty-one billion, five hundred fifty-three million, sixty-five thousand, four hundred twenty".