1981851700 has 36 divisors (see below), whose sum is σ = 4439354752. Its totient is φ = 767167200.

The previous prime is 1981851671. The next prime is 1981851719. The reversal of 1981851700 is 71581891.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 316554 + ... + 322753.

Almost surely, 2^1981851700 is an apocalyptic number.

1981851700 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1981851700 is an abundant number, since it is smaller than the sum of its proper divisors (2457503052).

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

1981851700 is a wasteful number, since it uses less digits than its factorization.

1981851700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 639352 (or 639345 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 40.

The square root of 1981851700 is about 44517.9929915984. The cubic root of 1981851700 is about 1256.0985603279.

The spelling of 1981851700 in words is "one billion, nine hundred eighty-one million, eight hundred fifty-one thousand, seven hundred".