21231330947 has 2 divisors, whose sum is σ = 21231330948. Its totient is φ = 21231330946.

The previous prime is 21231330937. The next prime is 21231330961. The reversal of 21231330947 is 74903313212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21231330947 is a prime.

It is not a weakly prime, because it can be changed into another prime (21231330937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615665473 + 10615665474.

It is an arithmetic number, because the mean of its divisors is an integer number (10615665474).

Almost surely, 2^21231330947 is an apocalyptic number.

21231330947 is a deficient number, since it is larger than the sum of its proper divisors (1).

21231330947 is an equidigital number, since it uses as much as digits as its factorization.

21231330947 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27216, while the sum is 35.

The spelling of 21231330947 in words is "twenty-one billion, two hundred thirty-one million, three hundred thirty thousand, nine hundred forty-seven".