21173878151 has 2 divisors, whose sum is σ = 21173878152. Its totient is φ = 21173878150.

The previous prime is 21173878139. The next prime is 21173878181. The reversal of 21173878151 is 15187837112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21173878151 - 2⁶ = 21173878087 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21173878111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10586939075 + 10586939076.

It is an arithmetic number, because the mean of its divisors is an integer number (10586939076).

Almost surely, 2^21173878151 is an apocalyptic number.

21173878151 is a deficient number, since it is larger than the sum of its proper divisors (1).

21173878151 is an equidigital number, since it uses as much as digits as its factorization.

21173878151 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 94080, while the sum is 44.

The spelling of 21173878151 in words is "twenty-one billion, one hundred seventy-three million, eight hundred seventy-eight thousand, one hundred fifty-one".