1981897275 has 24 divisors (see below), whose sum is σ = 3291200064. Its totient is φ = 1052346400.

The previous prime is 1981897273. The next prime is 1981897283. The reversal of 1981897275 is 5727981891.

It is not a de Polignac number, because 1981897275 - 2¹ = 1981897273 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1981897273) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41181 + ... + 75230.

It is an arithmetic number, because the mean of its divisors is an integer number (137133336).

Almost surely, 2^1981897275 is an apocalyptic number.

1981897275 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1981897275 is a deficient number, since it is larger than the sum of its proper divisors (1309302789).

1981897275 is a wasteful number, since it uses less digits than its factorization.

1981897275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116651 (or 116646 counting only the distinct ones).

The product of its digits is 2540160, while the sum is 57.

The square root of 1981897275 is about 44518.5048603387. The cubic root of 1981897275 is about 1256.1081887397.

The spelling of 1981897275 in words is "one billion, nine hundred eighty-one million, eight hundred ninety-seven thousand, two hundred seventy-five".