21009571220772 has 48 divisors (see below), whose sum is σ = 54491519013120. Its totient is φ = 7000328369376.

The previous prime is 21009571220747. The next prime is 21009571220791. The reversal of 21009571220772 is 27702217590012.

21009571220772 is a `hidden beast` number, since 2 + 1 + 0 + 0 + 9 + 571 + 2 + 2 + 0 + 7 + 72 = 666.

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, 39485023 + ... + 40013574.

It is an arithmetic number, because the mean of its divisors is an integer number (1135239979440).

Almost surely, 2^{21009571220772} is an apocalyptic number.

It is an amenable number.

21009571220772 is an abundant number, since it is smaller than the sum of its proper divisors (33481947792348).

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

21009571220772 is a wasteful number, since it uses less digits than its factorization.

21009571220772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79501057 (or 79501049 counting only the distinct ones).

The product of its (nonzero) digits is 246960, while the sum is 45.

The spelling of 21009571220772 in words is "twenty-one trillion, nine billion, five hundred seventy-one million, two hundred twenty thousand, seven hundred seventy-two".