21521697299999 has 4 divisors (see below), whose sum is σ = 23177212476936. Its totient is φ = 19866182123064.

The previous prime is 21521697299983. The next prime is 21521697300001. The reversal of 21521697299999 is 99999279612512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21521697299999 - 2⁴ = 21521697299983 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 (21521697299939) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 827757588449 + ... + 827757588474.

It is an arithmetic number, because the mean of its divisors is an integer number (5794303119234).

Almost surely, 2^{21521697299999} is an apocalyptic number.

21521697299999 is a deficient number, since it is larger than the sum of its proper divisors (1655515176937).

21521697299999 is a wasteful number, since it uses less digits than its factorization.

21521697299999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1655515176936.

The product of its digits is 892820880, while the sum is 80.

The spelling of 21521697299999 in words is "twenty-one trillion, five hundred twenty-one billion, six hundred ninety-seven million, two hundred ninety-nine thousand, nine hundred ninety-nine".