21581708286 has 16 divisors (see below), whose sum is σ = 43608401424. Its totient is φ = 7119738624.

The previous prime is 21581708263. The next prime is 21581708311. The reversal of 21581708286 is 68280718512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18540405 + ... + 18541568.

It is an arithmetic number, because the mean of its divisors is an integer number (2725525089).

Almost surely, 2^21581708286 is an apocalyptic number.

21581708286 is an abundant number, since it is smaller than the sum of its proper divisors (22026693138).

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

21581708286 is a wasteful number, since it uses less digits than its factorization.

21581708286 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37082075.

The product of its (nonzero) digits is 430080, while the sum is 48.

The spelling of 21581708286 in words is "twenty-one billion, five hundred eighty-one million, seven hundred eight thousand, two hundred eighty-six".