21778757532 has 144 divisors (see below), whose sum is σ = 64202890752. Its totient is φ = 6096090240.

The previous prime is 21778757491. The next prime is 21778757597. The reversal of 21778757532 is 23575787712.

21778757532 is a `hidden beast` number, since 21 + 7 + 7 + 87 + 5 + 7 + 532 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4040143 + ... + 4045529.

It is an arithmetic number, because the mean of its divisors is an integer number (445853408).

Almost surely, 2^21778757532 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 21778757532, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32101445376).

21778757532 is an abundant number, since it is smaller than the sum of its proper divisors (42424133220).

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

21778757532 is a wasteful number, since it uses less digits than its factorization.

21778757532 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5728 (or 5723 counting only the distinct ones).

The product of its digits is 5762400, while the sum is 54.

The spelling of 21778757532 in words is "twenty-one billion, seven hundred seventy-eight million, seven hundred fifty-seven thousand, five hundred thirty-two".