21002112415 has 4 divisors (see below), whose sum is σ = 25202534904. Its totient is φ = 16801689928.

The previous prime is 21002112371. The next prime is 21002112433. The reversal of 21002112415 is 51421120012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21002112415 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21002112392 and 21002112401.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2100211237 + ... + 2100211246.

It is an arithmetic number, because the mean of its divisors is an integer number (6300633726).

Almost surely, 2^21002112415 is an apocalyptic number.

21002112415 is a deficient number, since it is larger than the sum of its proper divisors (4200422489).

21002112415 is an equidigital number, since it uses as much as digits as its factorization.

21002112415 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4200422488.

The product of its (nonzero) digits is 160, while the sum is 19.

Adding to 21002112415 its reverse (51421120012), we get a palindrome (72423232427).

The spelling of 21002112415 in words is "twenty-one billion, two million, one hundred twelve thousand, four hundred fifteen".