21253149456 has 240 divisors, whose sum is σ = 70105512960. Its totient is φ = 5486127360.

The previous prime is 21253149451. The next prime is 21253149457. The reversal of 21253149456 is 65494135212.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (21253149451) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4318165 + ... + 4323083.

It is an arithmetic number, because the mean of its divisors is an integer number (292106304).

Almost surely, 2^21253149456 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21253149456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35052756480).

21253149456 is an abundant number, since it is smaller than the sum of its proper divisors (48852363504).

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

21253149456 is a wasteful number, since it uses less digits than its factorization.

21253149456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5122 (or 5109 counting only the distinct ones).

The product of its digits is 259200, while the sum is 42.

The spelling of 21253149456 in words is "twenty-one billion, two hundred fifty-three million, one hundred forty-nine thousand, four hundred fifty-six".