21656770423 has 8 divisors (see below), whose sum is σ = 22459999680. Its totient is φ = 20857304160.

The previous prime is 21656770417. The next prime is 21656770463. The reversal of 21656770423 is 32407765612.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21656770423 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21656770423.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21656770463) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 929023 + ... + 952048.

It is an arithmetic number, because the mean of its divisors is an integer number (2807499960).

Almost surely, 2^21656770423 is an apocalyptic number.

21656770423 is a deficient number, since it is larger than the sum of its proper divisors (803229257).

21656770423 is a wasteful number, since it uses less digits than its factorization.

21656770423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1881497.

The product of its (nonzero) digits is 423360, while the sum is 43.

The spelling of 21656770423 in words is "twenty-one billion, six hundred fifty-six million, seven hundred seventy thousand, four hundred twenty-three".