1981518020 has 24 divisors (see below), whose sum is σ = 4200081984. Its totient is φ = 785198816.

The previous prime is 1981517981. The next prime is 1981518089. The reversal of 1981518020 is 208151891.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 460832 + ... + 465111.

It is an arithmetic number, because the mean of its divisors is an integer number (175003416).

Almost surely, 2^1981518020 is an apocalyptic number.

1981518020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1981518020 is an abundant number, since it is smaller than the sum of its proper divisors (2218563964).

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

1981518020 is a wasteful number, since it uses less digits than its factorization.

1981518020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 926059 (or 926057 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 35.

The square root of 1981518020 is about 44514.2451356866. The cubic root of 1981518020 is about 1256.0280608563.

The spelling of 1981518020 in words is "one billion, nine hundred eighty-one million, five hundred eighteen thousand, twenty".