21256266773 has 8 divisors (see below), whose sum is σ = 24294204480. Its totient is φ = 18218661120.

The previous prime is 21256266767. The next prime is 21256266781. The reversal of 21256266773 is 37766265212.

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

It is a cyclic number.

It is not a de Polignac number, because 21256266773 - 2¹⁸ = 21256004629 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21256266743) 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, 73958 + ... + 219048.

It is an arithmetic number, because the mean of its divisors is an integer number (3036775560).

Almost surely, 2^21256266773 is an apocalyptic number.

It is an amenable number.

21256266773 is a deficient number, since it is larger than the sum of its proper divisors (3037937707).

21256266773 is a wasteful number, since it uses less digits than its factorization.

21256266773 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166027.

The product of its digits is 1270080, while the sum is 47.

The spelling of 21256266773 in words is "twenty-one billion, two hundred fifty-six million, two hundred sixty-six thousand, seven hundred seventy-three".