21297873415 has 16 divisors (see below), whose sum is σ = 31455321408. Its totient is φ = 13480851456.

The previous prime is 21297873409. The next prime is 21297873419. The reversal of 21297873415 is 51437879212.

It is a cyclic number.

It is not a de Polignac number, because 21297873415 - 2⁹ = 21297872903 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21297873419) 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, 23403802 + ... + 23404711.

It is an arithmetic number, because the mean of its divisors is an integer number (1965957588).

Almost surely, 2^21297873415 is an apocalyptic number.

21297873415 is a deficient number, since it is larger than the sum of its proper divisors (10157447993).

21297873415 is a wasteful number, since it uses less digits than its factorization.

21297873415 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46808538.

The product of its digits is 846720, while the sum is 49.

The spelling of 21297873415 in words is "twenty-one billion, two hundred ninety-seven million, eight hundred seventy-three thousand, four hundred fifteen".