21081477478450 has 24 divisors (see below), whose sum is σ = 39854360379780. Its totient is φ = 8294351793600.

The previous prime is 21081477478441. The next prime is 21081477478489. The reversal of 21081477478450 is 5487477418012.

It can be written as a sum of positive squares in 6 ways, for example, as 8812829386881 + 12268648091569 = 2968641^2 + 3502663^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3455976865 + ... + 3455982964.

Almost surely, 2^{21081477478450} is an apocalyptic number.

21081477478450 is a deficient number, since it is larger than the sum of its proper divisors (18772882901330).

21081477478450 is a wasteful number, since it uses less digits than its factorization.

21081477478450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6911959902 (or 6911959897 counting only the distinct ones).

The product of its (nonzero) digits is 14049280, while the sum is 58.

The spelling of 21081477478450 in words is "twenty-one trillion, eighty-one billion, four hundred seventy-seven million, four hundred seventy-eight thousand, four hundred fifty".