2157209851 has 2 divisors, whose sum is σ = 2157209852. Its totient is φ = 2157209850.

The previous prime is 2157209837. The next prime is 2157209867. The reversal of 2157209851 is 1589027512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2157209851 - 2¹¹ = 2157207803 is a prime.

It is not a weakly prime, because it can be changed into another prime (2157209801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1078604925 + 1078604926.

It is an arithmetic number, because the mean of its divisors is an integer number (1078604926).

Almost surely, 2^2157209851 is an apocalyptic number.

2157209851 is a deficient number, since it is larger than the sum of its proper divisors (1).

2157209851 is an equidigital number, since it uses as much as digits as its factorization.

2157209851 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 50400, while the sum is 40.

The square root of 2157209851 is about 46445.7732307257. The cubic root of 2157209851 is about 1292.1039821723.

The spelling of 2157209851 in words is "two billion, one hundred fifty-seven million, two hundred nine thousand, eight hundred fifty-one".