21597849460 has 24 divisors (see below), whose sum is σ = 49478710176. Its totient is φ = 7853763360.

The previous prime is 21597849439. The next prime is 21597849509. The reversal of 21597849460 is 6494879512.

It is a Harshad number since it is a multiple of its sum of digits (55).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49085802 + ... + 49086241.

It is an arithmetic number, because the mean of its divisors is an integer number (2061612924).

Almost surely, 2^21597849460 is an apocalyptic number.

21597849460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21597849460 is an abundant number, since it is smaller than the sum of its proper divisors (27880860716).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21597849460 is a wasteful number, since it uses less digits than its factorization.

21597849460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98172063 (or 98172061 counting only the distinct ones).

The product of its (nonzero) digits is 4354560, while the sum is 55.

The spelling of 21597849460 in words is "twenty-one billion, five hundred ninety-seven million, eight hundred forty-nine thousand, four hundred sixty".