21546749952 has 416 divisors, whose sum is σ = 78602146560. Its totient is φ = 5680005120.

The previous prime is 21546749897. The next prime is 21546749953. The reversal of 21546749952 is 25994764512.

It is a happy number.

21546749952 is a `hidden beast` number, since 2 + 1 + 546 + 7 + 4 + 9 + 95 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (416).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21546749953) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10062802 + ... + 10064942.

Almost surely, 2^21546749952 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 21546749952, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39301073280).

21546749952 is an abundant number, since it is smaller than the sum of its proper divisors (57055396608).

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

21546749952 is a wasteful number, since it uses less digits than its factorization.

21546749952 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2194 (or 2166 counting only the distinct ones).

The product of its digits is 5443200, while the sum is 54.

The spelling of 21546749952 in words is "twenty-one billion, five hundred forty-six million, seven hundred forty-nine thousand, nine hundred fifty-two".