21670447361 has 4 divisors (see below), whose sum is σ = 21826350000. Its totient is φ = 21514544724.

The previous prime is 21670447343. The next prime is 21670447363. The reversal of 21670447361 is 16374407612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21670447361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21670447363) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77951111 + ... + 77951388.

It is an arithmetic number, because the mean of its divisors is an integer number (5456587500).

Almost surely, 2^21670447361 is an apocalyptic number.

It is an amenable number.

21670447361 is a deficient number, since it is larger than the sum of its proper divisors (155902639).

21670447361 is a wasteful number, since it uses less digits than its factorization.

21670447361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155902638.

The product of its (nonzero) digits is 169344, while the sum is 41.

The spelling of 21670447361 in words is "twenty-one billion, six hundred seventy million, four hundred forty-seven thousand, three hundred sixty-one".