21661630147 has 2 divisors, whose sum is σ = 21661630148. Its totient is φ = 21661630146.

The previous prime is 21661630139. The next prime is 21661630169. The reversal of 21661630147 is 74103616612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21661630147 - 2³ = 21661630139 is a prime.

It is not a weakly prime, because it can be changed into another prime (21661630117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10830815073 + 10830815074.

It is an arithmetic number, because the mean of its divisors is an integer number (10830815074).

Almost surely, 2^21661630147 is an apocalyptic number.

21661630147 is a deficient number, since it is larger than the sum of its proper divisors (1).

21661630147 is an equidigital number, since it uses as much as digits as its factorization.

21661630147 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36288, while the sum is 37.

The spelling of 21661630147 in words is "twenty-one billion, six hundred sixty-one million, six hundred thirty thousand, one hundred forty-seven".