1851898891 has 2 divisors, whose sum is σ = 1851898892. Its totient is φ = 1851898890.

The previous prime is 1851898837. The next prime is 1851898901. The reversal of 1851898891 is 1988981581.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1851898891 - 2¹⁵ = 1851866123 is a prime.

It is not a weakly prime, because it can be changed into another prime (1851890891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 925949445 + 925949446.

It is an arithmetic number, because the mean of its divisors is an integer number (925949446).

Almost surely, 2^1851898891 is an apocalyptic number.

1851898891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1851898891 is an equidigital number, since it uses as much as digits as its factorization.

1851898891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1658880, while the sum is 58.

The square root of 1851898891 is about 43033.6948332350. The cubic root of 1851898891 is about 1228.0208970810.

The spelling of 1851898891 in words is "one billion, eight hundred fifty-one million, eight hundred ninety-eight thousand, eight hundred ninety-one".