21201220015 has 16 divisors (see below), whose sum is σ = 26898491520. Its totient is φ = 15997491360.

The previous prime is 21201219997. The next prime is 21201220031. The reversal of 21201220015 is 51002210212.

It is a happy number.

It is not a de Polignac number, because 21201220015 - 2²⁷ = 21067002287 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 470001 + ... + 513130.

It is an arithmetic number, because the mean of its divisors is an integer number (1681155720).

Almost surely, 2^21201220015 is an apocalyptic number.

21201220015 is a deficient number, since it is larger than the sum of its proper divisors (5697271505).

21201220015 is a wasteful number, since it uses less digits than its factorization.

21201220015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 983382.

The product of its (nonzero) digits is 80, while the sum is 16.

Adding to 21201220015 its reverse (51002210212), we get a palindrome (72203430227).

The spelling of 21201220015 in words is "twenty-one billion, two hundred one million, two hundred twenty thousand, fifteen".