21406661703 has 72 divisors (see below), whose sum is σ = 36294535680. Its totient is φ = 12122278560.

The previous prime is 21406661641. The next prime is 21406661707. The reversal of 21406661703 is 30716660412.

It is a happy number.

It is not a de Polignac number, because 21406661703 - 2⁸ = 21406661447 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21406661707) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 35266026 + ... + 35266632.

Almost surely, 2^21406661703 is an apocalyptic number.

21406661703 is a deficient number, since it is larger than the sum of its proper divisors (14887873977).

21406661703 is a wasteful number, since it uses less digits than its factorization.

21406661703 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1217 (or 1207 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 36.

The spelling of 21406661703 in words is "twenty-one billion, four hundred six million, six hundred sixty-one thousand, seven hundred three".