21366581012 has 24 divisors (see below), whose sum is σ = 42736365504. Its totient is φ = 9156419712.

The previous prime is 21366580979. The next prime is 21366581017. The reversal of 21366581012 is 21018566312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21366581017) 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, 575228 + ... + 611244.

It is an arithmetic number, because the mean of its divisors is an integer number (1780681896).

Almost surely, 2^21366581012 is an apocalyptic number.

It is an amenable number.

21366581012 is an abundant number, since it is smaller than the sum of its proper divisors (21369784492).

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

21366581012 is a wasteful number, since it uses less digits than its factorization.

21366581012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57215 (or 57213 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 35.

The spelling of 21366581012 in words is "twenty-one billion, three hundred sixty-six million, five hundred eighty-one thousand, twelve".