21947829904 has 405 divisors, whose sum is σ = 60510867291. Its totient is φ = 7679992320.

The previous prime is 21947829899. The next prime is 21947829919. The reversal of 21947829904 is 40992874912.

It is a happy number.

The square root of 21947829904 is 148148.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 91164304 + 21856665600 = 9548^2 + 147840^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 593184574 + ... + 593184610.

Almost surely, 2^21947829904 is an apocalyptic number.

21947829904 is the 148148-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21947829904

21947829904 is an abundant number, since it is smaller than the sum of its proper divisors (38563037387).

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

21947829904 is a wasteful number, since it uses less digits than its factorization.

21947829904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144 (or 70 counting only the distinct ones).

The product of its (nonzero) digits is 2612736, while the sum is 55.

The spelling of 21947829904 in words is "twenty-one billion, nine hundred forty-seven million, eight hundred twenty-nine thousand, nine hundred four".