21261715430 has 32 divisors (see below), whose sum is σ = 39946293504. Its totient is φ = 8132626656.

The previous prime is 21261715403. The next prime is 21261715439. The reversal of 21261715430 is 3451716212.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21261715439) 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, 964997 + ... + 986783.

It is an arithmetic number, because the mean of its divisors is an integer number (1248321672).

Almost surely, 2^21261715430 is an apocalyptic number.

21261715430 is a deficient number, since it is larger than the sum of its proper divisors (18684578074).

21261715430 is a wasteful number, since it uses less digits than its factorization.

21261715430 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26060.

The product of its (nonzero) digits is 10080, while the sum is 32.

The spelling of 21261715430 in words is "twenty-one billion, two hundred sixty-one million, seven hundred fifteen thousand, four hundred thirty".