21401020015 has 16 divisors (see below), whose sum is σ = 25890011136. Its totient is φ = 16981754400.

The previous prime is 21401020001. The next prime is 21401020019. The reversal of 21401020015 is 51002010412.

It is not a de Polignac number, because 21401020015 - 2¹⁵ = 21400987247 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 (21401020019) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1554010 + ... + 1567720.

It is an arithmetic number, because the mean of its divisors is an integer number (1618125696).

Almost surely, 2^21401020015 is an apocalyptic number.

21401020015 is a deficient number, since it is larger than the sum of its proper divisors (4488991121).

21401020015 is a wasteful number, since it uses less digits than its factorization.

21401020015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16230.

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

Adding to 21401020015 its reverse (51002010412), we get a palindrome (72403030427).

The spelling of 21401020015 in words is "twenty-one billion, four hundred one million, twenty thousand, fifteen".