21870396576 has 756 divisors, whose sum is σ = 80752188762. Its totient is φ = 5808112128.

The previous prime is 21870396571. The next prime is 21870396601. The reversal of 21870396576 is 67569307812.

21870396576 is a `hidden beast` number, since 2 + 187 + 0 + 396 + 5 + 76 = 666.

It can be written as a sum of positive squares in only one way, i.e., 16712284176 + 5158112400 = 129276^2 + 71820^2 .

It is a tau number, because it is divible by the number of its divisors (756).

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

It is not an unprimeable number, because it can be changed into a prime (21870396571) by changing a digit.

It is a polite number, since it can be written in 125 ways as a sum of consecutive naturals, for example, 412648966 + ... + 412649018.

Almost surely, 2^21870396576 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 21870396576, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40376094381).

21870396576 is an abundant number, since it is smaller than the sum of its proper divisors (58881792186).

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

21870396576 is an equidigital number, since it uses as much as digits as its factorization.

21870396576 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133 (or 84 counting only the distinct ones).

The product of its (nonzero) digits is 3810240, while the sum is 54.

The spelling of 21870396576 in words is "twenty-one billion, eight hundred seventy million, three hundred ninety-six thousand, five hundred seventy-six".