21153591572 has 12 divisors (see below), whose sum is σ = 39196360980. Its totient is φ = 9954631296.

The previous prime is 21153591509. The next prime is 21153591583. The reversal of 21153591572 is 27519535112.

It can be written as a sum of positive squares in 2 ways, for example, as 12958634896 + 8194956676 = 113836^2 + 90526^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 155541047 + ... + 155541182.

It is an arithmetic number, because the mean of its divisors is an integer number (3266363415).

Almost surely, 2^21153591572 is an apocalyptic number.

It is an amenable number.

21153591572 is a deficient number, since it is larger than the sum of its proper divisors (18042769408).

21153591572 is a wasteful number, since it uses less digits than its factorization.

21153591572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311082250 (or 311082248 counting only the distinct ones).

The product of its digits is 94500, while the sum is 41.

The spelling of 21153591572 in words is "twenty-one billion, one hundred fifty-three million, five hundred ninety-one thousand, five hundred seventy-two".