21352051999 has 4 divisors (see below), whose sum is σ = 21644545936. Its totient is φ = 21059558064.

The previous prime is 21352051997. The next prime is 21352052023. The reversal of 21352051999 is 99915025312.

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 21352051999 - 2¹ = 21352051997 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 (21352051997) 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, 146246859 + ... + 146247004.

It is an arithmetic number, because the mean of its divisors is an integer number (5411136484).

Almost surely, 2^21352051999 is an apocalyptic number.

21352051999 is a deficient number, since it is larger than the sum of its proper divisors (292493937).

21352051999 is an equidigital number, since it uses as much as digits as its factorization.

21352051999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 292493936.

The product of its (nonzero) digits is 218700, while the sum is 46.

The spelling of 21352051999 in words is "twenty-one billion, three hundred fifty-two million, fifty-one thousand, nine hundred ninety-nine".