21802261866 has 32 divisors (see below), whose sum is σ = 54364082688. Its totient is φ = 5662925040.

The previous prime is 21802261861. The next prime is 21802261931. The reversal of 21802261866 is 66816220812.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (21802261861) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23595060 + ... + 23595983.

It is an arithmetic number, because the mean of its divisors is an integer number (1698877584).

Almost surely, 2^21802261866 is an apocalyptic number.

21802261866 is an abundant number, since it is smaller than the sum of its proper divisors (32561820822).

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

21802261866 is a wasteful number, since it uses less digits than its factorization.

21802261866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47191066.

The product of its (nonzero) digits is 110592, while the sum is 42.

The spelling of 21802261866 in words is "twenty-one billion, eight hundred two million, two hundred sixty-one thousand, eight hundred sixty-six".