21890091615 has 32 divisors (see below), whose sum is σ = 42134315520. Its totient is φ = 9480219264.

The previous prime is 21890091611. The next prime is 21890091649. The reversal of 21890091615 is 51619009812.

It is not a de Polignac number, because 21890091615 - 2² = 21890091611 is a prime.

It is a super-2 number, since 2×21890091615² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21890091611) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5484244 + ... + 5488233.

It is an arithmetic number, because the mean of its divisors is an integer number (1316697360).

Almost surely, 2^21890091615 is an apocalyptic number.

21890091615 is a deficient number, since it is larger than the sum of its proper divisors (20244223905).

21890091615 is a wasteful number, since it uses less digits than its factorization.

21890091615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10972511.

The product of its (nonzero) digits is 38880, while the sum is 42.

The spelling of 21890091615 in words is "twenty-one billion, eight hundred ninety million, ninety-one thousand, six hundred fifteen".