1987381251 has 10 divisors (see below), whose sum is σ = 2968804212. Its totient is φ = 1324920780.

The previous prime is 1987381199. The next prime is 1987381271. The reversal of 1987381251 is 1521837891.

1987381251 is a `hidden beast` number, since 19 + 8 + 7 + 381 + 251 = 666.

It is not a de Polignac number, because 1987381251 - 2¹⁵ = 1987348483 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1987381197 and 1987381206.

It is not an unprimeable number, because it can be changed into a prime (1987381271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 12267705 + ... + 12267866.

Almost surely, 2^1987381251 is an apocalyptic number.

1987381251 is a deficient number, since it is larger than the sum of its proper divisors (981422961).

1987381251 is an equidigital number, since it uses as much as digits as its factorization.

1987381251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24535583 (or 24535574 counting only the distinct ones).

The product of its digits is 120960, while the sum is 45.

The square root of 1987381251 is about 44580.0544077730. The cubic root of 1987381251 is about 1257.2656862307.

It can be divided in two parts, 19873 and 81251, that added together give a square (101124 = 318²).

The spelling of 1987381251 in words is "one billion, nine hundred eighty-seven million, three hundred eighty-one thousand, two hundred fifty-one".