21770643552 has 192 divisors, whose sum is σ = 66820723200. Its totient is φ = 6203785728.

The previous prime is 21770643533. The next prime is 21770643577. The reversal of 21770643552 is 25534607712.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18340303 + ... + 18341489.

It is an arithmetic number, because the mean of its divisors is an integer number (348024600).

Almost surely, 2^21770643552 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 21770643552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33410361600).

21770643552 is an abundant number, since it is smaller than the sum of its proper divisors (45050079648).

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

21770643552 is a wasteful number, since it uses less digits than its factorization.

21770643552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1778 (or 1756 counting only the distinct ones).

The product of its (nonzero) digits is 352800, while the sum is 42.

The spelling of 21770643552 in words is "twenty-one billion, seven hundred seventy million, six hundred forty-three thousand, five hundred fifty-two".