1540899981 has 36 divisors (see below), whose sum is σ = 2424988800. Its totient is φ = 941744880.

The previous prime is 1540899967. The next prime is 1540900001. The reversal of 1540899981 is 1899980451.

1540899981 is a `hidden beast` number, since 1 + 540 + 8 + 9 + 9 + 98 + 1 = 666.

It is not a de Polignac number, because 1540899981 - 2⁶ = 1540899917 is a prime.

It is a super-2 number, since 2×1540899981² = 4748745502891600722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1540899901) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 93070 + ... + 108368.

It is an arithmetic number, because the mean of its divisors is an integer number (67360800).

Almost surely, 2^1540899981 is an apocalyptic number.

It is an amenable number.

1540899981 is a deficient number, since it is larger than the sum of its proper divisors (884088819).

1540899981 is a wasteful number, since it uses less digits than its factorization.

1540899981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15374 (or 15352 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 54.

The square root of 1540899981 is about 39254.2988855998. The cubic root of 1540899981 is about 1155.0252628420.

The spelling of 1540899981 in words is "one billion, five hundred forty million, eight hundred ninety-nine thousand, nine hundred eighty-one".