21261021531599 has 8 divisors (see below), whose sum is σ = 21450094559712. Its totient is φ = 21071964686080.

The previous prime is 21261021531583. The next prime is 21261021531601. The reversal of 21261021531599 is 99513512016212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21261021531599 - 2⁴ = 21261021531583 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21261021521599) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1398659 + ... + 6669204.

It is an arithmetic number, because the mean of its divisors is an integer number (2681261819964).

Almost surely, 2^{21261021531599} is an apocalyptic number.

21261021531599 is a deficient number, since it is larger than the sum of its proper divisors (189073028113).

21261021531599 is a wasteful number, since it uses less digits than its factorization.

21261021531599 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8091297.

The product of its (nonzero) digits is 291600, while the sum is 47.

The spelling of 21261021531599 in words is "twenty-one trillion, two hundred sixty-one billion, twenty-one million, five hundred thirty-one thousand, five hundred ninety-nine".