21145972224 has 360 divisors, whose sum is σ = 64317524040. Its totient is φ = 6163562496.

The previous prime is 21145972213. The next prime is 21145972279. The reversal of 21145972224 is 42227954112.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 398980582 + ... + 398980634.

It is an arithmetic number, because the mean of its divisors is an integer number (178659789).

Almost surely, 2^21145972224 is an apocalyptic number.

21145972224 is a gapful number since it is divisible by the number (24) 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 21145972224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32158762020).

21145972224 is an abundant number, since it is smaller than the sum of its proper divisors (43171551816).

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

21145972224 is an equidigital number, since it uses as much as digits as its factorization.

21145972224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182 (or 100 counting only the distinct ones).

The product of its digits is 80640, while the sum is 39.

The spelling of 21145972224 in words is "twenty-one billion, one hundred forty-five million, nine hundred seventy-two thousand, two hundred twenty-four".