21012515203 has 4 divisors (see below), whose sum is σ = 21408977808. Its totient is φ = 20616052600.

The previous prime is 21012515137. The next prime is 21012515269. The reversal of 21012515203 is 30251521012.

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

It is an interprime number because it is at equal distance from previous prime (21012515137) and next prime (21012515269).

It is a cyclic number.

It is not a de Polignac number, because 21012515203 - 2¹⁷ = 21012384131 is a prime.

It is a super-2 number, since 2×21012515203² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21012512203) 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, 198231223 + ... + 198231328.

It is an arithmetic number, because the mean of its divisors is an integer number (5352244452).

Almost surely, 2^21012515203 is an apocalyptic number.

21012515203 is a deficient number, since it is larger than the sum of its proper divisors (396462605).

21012515203 is an equidigital number, since it uses as much as digits as its factorization.

21012515203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 396462604.

The product of its (nonzero) digits is 600, while the sum is 22.

The spelling of 21012515203 in words is "twenty-one billion, twelve million, five hundred fifteen thousand, two hundred three".