21768639570 has 256 divisors, whose sum is σ = 65882004480. Its totient is φ = 5083803648.

The previous prime is 21768639569. The next prime is 21768639601. The reversal of 21768639570 is 7593686712.

21768639570 is a `hidden beast` number, since 2 + 1 + 7 + 6 + 8 + 63 + 9 + 570 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 3903304 + ... + 3908876.

It is an arithmetic number, because the mean of its divisors is an integer number (257351580).

Almost surely, 2^21768639570 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21768639570, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32941002240).

21768639570 is an abundant number, since it is smaller than the sum of its proper divisors (44113364910).

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

21768639570 is a wasteful number, since it uses less digits than its factorization.

21768639570 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5666 (or 5660 counting only the distinct ones).

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

The spelling of 21768639570 in words is "twenty-one billion, seven hundred sixty-eight million, six hundred thirty-nine thousand, five hundred seventy".