21021790782 has 8 divisors (see below), whose sum is σ = 42043581576. Its totient is φ = 7007263592.

The previous prime is 21021790771. The next prime is 21021790787. The reversal of 21021790782 is 28709712012.

It is a sphenic number, since it is the product of 3 distinct primes.

21021790782 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 21021790782.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021790787) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1751815893 + ... + 1751815904.

It is an arithmetic number, because the mean of its divisors is an integer number (5255447697).

Almost surely, 2^21021790782 is an apocalyptic number.

21021790782 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21021790782 is a wasteful number, since it uses less digits than its factorization.

21021790782 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3503631802.

The product of its (nonzero) digits is 28224, while the sum is 39.

The spelling of 21021790782 in words is "twenty-one billion, twenty-one million, seven hundred ninety thousand, seven hundred eighty-two".