21002199975 has 36 divisors (see below), whose sum is σ = 38039976000. Its totient is φ = 11075306880.

The previous prime is 21002199973. The next prime is 21002199983. The reversal of 21002199975 is 57999120012.

It is not a de Polignac number, because 21002199975 - 2¹ = 21002199973 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 21002199975.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002199973) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 504375 + ... + 544424.

It is an arithmetic number, because the mean of its divisors is an integer number (1056666000).

Almost surely, 2^21002199975 is an apocalyptic number.

21002199975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21002199975 is a deficient number, since it is larger than the sum of its proper divisors (17037776025).

21002199975 is a wasteful number, since it uses less digits than its factorization.

21002199975 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1048904 (or 1048896 counting only the distinct ones).

The product of its (nonzero) digits is 102060, while the sum is 45.

The spelling of 21002199975 in words is "twenty-one billion, two million, one hundred ninety-nine thousand, nine hundred seventy-five".