21901215189 has 16 divisors (see below), whose sum is σ = 33412249728. Its totient is φ = 12500366592.

The previous prime is 21901215179. The next prime is 21901215223. The reversal of 21901215189 is 98151210912.

It is a happy number.

It is not a de Polignac number, because 21901215189 - 2²¹ = 21899118037 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21901215179) 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, 590472 + ... + 626465.

It is an arithmetic number, because the mean of its divisors is an integer number (2088265608).

Almost surely, 2^21901215189 is an apocalyptic number.

It is an amenable number.

21901215189 is a deficient number, since it is larger than the sum of its proper divisors (11511034539).

21901215189 is a wasteful number, since it uses less digits than its factorization.

21901215189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1217804.

The product of its (nonzero) digits is 12960, while the sum is 39.

The spelling of 21901215189 in words is "twenty-one billion, nine hundred one million, two hundred fifteen thousand, one hundred eighty-nine".