21059199840 has 96 divisors (see below), whose sum is σ = 75813131520. Its totient is φ = 4813530624.

The previous prime is 21059199839. The next prime is 21059199851. The reversal of 21059199840 is 4899195012.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 21059199840.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3130450 + ... + 3137169.

It is an arithmetic number, because the mean of its divisors is an integer number (789720120).

Almost surely, 2^21059199840 is an apocalyptic number.

21059199840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21059199840 is an abundant number, since it is smaller than the sum of its proper divisors (54753931680).

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

21059199840 is a wasteful number, since it uses less digits than its factorization.

21059199840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6267644 (or 6267636 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 48.

The spelling of 21059199840 in words is "twenty-one billion, fifty-nine million, one hundred ninety-nine thousand, eight hundred forty".