2157209867 has 2 divisors, whose sum is σ = 2157209868. Its totient is φ = 2157209866.

The previous prime is 2157209851. The next prime is 2157209893. The reversal of 2157209867 is 7689027512.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2157209867 - 2⁴ = 2157209851 is a prime.

It is not a weakly prime, because it can be changed into another prime (2157209837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1078604933 + 1078604934.

It is an arithmetic number, because the mean of its divisors is an integer number (1078604934).

Almost surely, 2^2157209867 is an apocalyptic number.

2157209867 is a deficient number, since it is larger than the sum of its proper divisors (1).

2157209867 is an equidigital number, since it uses as much as digits as its factorization.

2157209867 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 423360, while the sum is 47.

The square root of 2157209867 is about 46445.7734029696. The cubic root of 2157209867 is about 1292.1039853668.

The spelling of 2157209867 in words is "two billion, one hundred fifty-seven million, two hundred nine thousand, eight hundred sixty-seven".