21181640467 has 16 divisors (see below), whose sum is σ = 24184917792. Its totient is φ = 18377694720.

The previous prime is 21181640461. The next prime is 21181640471. The reversal of 21181640467 is 76404618112.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21181640467 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21181640461) 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, 103992 + ... + 230602.

It is an arithmetic number, because the mean of its divisors is an integer number (1511557362).

Almost surely, 2^21181640467 is an apocalyptic number.

21181640467 is a deficient number, since it is larger than the sum of its proper divisors (3003277325).

21181640467 is a wasteful number, since it uses less digits than its factorization.

21181640467 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127398.

The product of its (nonzero) digits is 64512, while the sum is 40.

The spelling of 21181640467 in words is "twenty-one billion, one hundred eighty-one million, six hundred forty thousand, four hundred sixty-seven".