21213491760 has 560 divisors, whose sum is σ = 77139393120. Its totient is φ = 5419560960.

The previous prime is 21213491749. The next prime is 21213491833. The reversal of 21213491760 is 6719431212.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 238353796 + ... + 238353884.

Almost surely, 2^21213491760 is an apocalyptic number.

21213491760 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21213491760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38569696560).

21213491760 is an abundant number, since it is smaller than the sum of its proper divisors (55925901360).

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

21213491760 is an equidigital number, since it uses as much as digits as its factorization.

21213491760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 248 (or 227 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The spelling of 21213491760 in words is "twenty-one billion, two hundred thirteen million, four hundred ninety-one thousand, seven hundred sixty".