21706409290 has 8 divisors (see below), whose sum is σ = 39071536740. Its totient is φ = 8682563712.

The previous prime is 21706409287. The next prime is 21706409327. The reversal of 21706409290 is 9290460712.

It can be written as a sum of positive squares in 2 ways, for example, as 20258682889 + 1447726401 = 142333^2 + 38049^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1085320455 + ... + 1085320474.

Almost surely, 2^21706409290 is an apocalyptic number.

21706409290 is a deficient number, since it is larger than the sum of its proper divisors (17365127450).

21706409290 is a wasteful number, since it uses less digits than its factorization.

21706409290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2170640936.

The product of its (nonzero) digits is 54432, while the sum is 40.

The spelling of 21706409290 in words is "twenty-one billion, seven hundred six million, four hundred nine thousand, two hundred ninety".