1801991051 has 16 divisors (see below), whose sum is σ = 2157179904. Its totient is φ = 1471756704.

The previous prime is 1801991021. The next prime is 1801991053. The reversal of 1801991051 is 1501991081.

It is a cyclic number.

It is not a de Polignac number, because 1801991051 - 2⁶ = 1801990987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1801991053) 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, 21065 + ... + 63621.

It is an arithmetic number, because the mean of its divisors is an integer number (134823744).

Almost surely, 2^1801991051 is an apocalyptic number.

1801991051 is a deficient number, since it is larger than the sum of its proper divisors (355188853).

1801991051 is a wasteful number, since it uses less digits than its factorization.

1801991051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42850.

The product of its (nonzero) digits is 3240, while the sum is 35.

The square root of 1801991051 is about 42449.8651470178. The cubic root of 1801991051 is about 1216.8887514110. Note that the first 3 decimals are identical.

The spelling of 1801991051 in words is "one billion, eight hundred one million, nine hundred ninety-one thousand, fifty-one".