21801225672 has 36 divisors (see below), whose sum is σ = 59048379585. Its totient is φ = 7266657600.

The previous prime is 21801225653. The next prime is 21801225769. The reversal of 21801225672 is 27652210812.

It is a happy number.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

21801225672 is a `hidden beast` number, since 2 + 1 + 80 + 12 + 2 + 567 + 2 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 21628408356 + 172817316 = 147066^2 + 13146^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=104406.

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 8 ways as a sum of consecutive naturals, for example, 1244172 + ... + 1261572.

Almost surely, 2^21801225672 is an apocalyptic number.

It is an amenable number.

21801225672 is an abundant number, since it is smaller than the sum of its proper divisors (37247153913).

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

21801225672 is an frugal number, since it uses more digits than its factorization.

21801225672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34814 (or 17406 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The spelling of 21801225672 in words is "twenty-one billion, eight hundred one million, two hundred twenty-five thousand, six hundred seventy-two".