21149496720 has 240 divisors, whose sum is σ = 78198120000. Its totient is φ = 5079905280.

The previous prime is 21149496707. The next prime is 21149496737. The reversal of 21149496720 is 2769494112.

21149496720 is a `hidden beast` number, since 2 + 1 + 1 + 494 + 96 + 72 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 851031 + ... + 875529.

It is an arithmetic number, because the mean of its divisors is an integer number (325825500).

Almost surely, 2^21149496720 is an apocalyptic number.

21149496720 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 21149496720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39099060000).

21149496720 is an abundant number, since it is smaller than the sum of its proper divisors (57048623280).

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

21149496720 is a wasteful number, since it uses less digits than its factorization.

21149496720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24638 (or 24629 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The spelling of 21149496720 in words is "twenty-one billion, one hundred forty-nine million, four hundred ninety-six thousand, seven hundred twenty".