21786421266 has 48 divisors (see below), whose sum is σ = 48264263424. Its totient is φ = 7099369152.

The previous prime is 21786421133. The next prime is 21786421369. The reversal of 21786421266 is 66212468712.

21786421266 is a `hidden beast` number, since 217 + 8 + 6 + 421 + 2 + 6 + 6 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 735886 + ... + 764918.

It is an arithmetic number, because the mean of its divisors is an integer number (1005505488).

Almost surely, 2^21786421266 is an apocalyptic number.

21786421266 is an abundant number, since it is smaller than the sum of its proper divisors (26477842158).

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

21786421266 is a wasteful number, since it uses less digits than its factorization.

21786421266 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29975 (or 29972 counting only the distinct ones).

The product of its digits is 387072, while the sum is 45.

Adding to 21786421266 its reverse (66212468712), we get a palindrome (87998889978).

The spelling of 21786421266 in words is "twenty-one billion, seven hundred eighty-six million, four hundred twenty-one thousand, two hundred sixty-six".