21500153550 has 36 divisors (see below), whose sum is σ = 57763747080. Its totient is φ = 5733374160.

The previous prime is 21500153539. The next prime is 21500153569. The reversal of 21500153550 is 5535100512.

21500153550 is a `hidden beast` number, since 2 + 1 + 500 + 153 + 5 + 5 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 23888610 + ... + 23889509.

It is an arithmetic number, because the mean of its divisors is an integer number (1604548530).

Almost surely, 2^21500153550 is an apocalyptic number.

21500153550 is an abundant number, since it is smaller than the sum of its proper divisors (36263593530).

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

21500153550 is a wasteful number, since it uses less digits than its factorization.

21500153550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47778137 (or 47778129 counting only the distinct ones).

The product of its (nonzero) digits is 3750, while the sum is 27.

The spelling of 21500153550 in words is "twenty-one billion, five hundred million, one hundred fifty-three thousand, five hundred fifty".