1851994540 has 36 divisors (see below), whose sum is σ = 4274898768. Its totient is φ = 673451680.

The previous prime is 1851994537. The next prime is 1851994541. The reversal of 1851994540 is 454991581.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (1851994541) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 380224 + ... + 385063.

It is an arithmetic number, because the mean of its divisors is an integer number (118747188).

Almost surely, 2^1851994540 is an apocalyptic number.

1851994540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1851994540 is an abundant number, since it is smaller than the sum of its proper divisors (2422904228).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1851994540 is a wasteful number, since it uses less digits than its factorization.

1851994540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 765318 (or 765305 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 46.

The square root of 1851994540 is about 43034.8061457235. The cubic root of 1851994540 is about 1228.0420387947.

The spelling of 1851994540 in words is "one billion, eight hundred fifty-one million, nine hundred ninety-four thousand, five hundred forty".