21075662790 has 768 divisors, whose sum is σ = 77894369280. Its totient is φ = 3822059520.

The previous prime is 21075662789. The next prime is 21075662801. The reversal of 21075662790 is 9726657012.

21075662790 is a `hidden beast` number, since 2 + 10 + 7 + 5 + 6 + 627 + 9 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 82006342 + ... + 82006598.

It is an arithmetic number, because the mean of its divisors is an integer number (101424960).

Almost surely, 2^21075662790 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21075662790, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38947184640).

21075662790 is an abundant number, since it is smaller than the sum of its proper divisors (56818706490).

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

21075662790 is a wasteful number, since it uses less digits than its factorization.

21075662790 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 357 (or 354 counting only the distinct ones).

The product of its (nonzero) digits is 317520, while the sum is 45.

It can be divided in two parts, 21075 and 662790, that added together give a triangular number (683865 = T₁₁₆₉).

The spelling of 21075662790 in words is "twenty-one billion, seventy-five million, six hundred sixty-two thousand, seven hundred ninety".