21869409957 has 4 divisors (see below), whose sum is σ = 29159213280. Its totient is φ = 14579606636.

The previous prime is 21869409949. The next prime is 21869409967. The reversal of 21869409957 is 75990496812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21869409957 - 2³ = 21869409949 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21869409957.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21869409967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3644901657 + ... + 3644901662.

It is an arithmetic number, because the mean of its divisors is an integer number (7289803320).

Almost surely, 2^21869409957 is an apocalyptic number.

It is an amenable number.

21869409957 is a deficient number, since it is larger than the sum of its proper divisors (7289803323).

21869409957 is an equidigital number, since it uses as much as digits as its factorization.

21869409957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7289803322.

The product of its (nonzero) digits is 9797760, while the sum is 60.

The spelling of 21869409957 in words is "twenty-one billion, eight hundred sixty-nine million, four hundred nine thousand, nine hundred fifty-seven".