1987391493 has 24 divisors (see below), whose sum is σ = 3003902720. Its totient is φ = 1264610880.

The previous prime is 1987391479. The next prime is 1987391533. The reversal of 1987391493 is 3941937891.

It is a happy number.

It is not a de Polignac number, because 1987391493 - 2¹³ = 1987383301 is a prime.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1987391993) 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, 28423 + ... + 69156.

Almost surely, 2^1987391493 is an apocalyptic number.

It is an amenable number.

1987391493 is a deficient number, since it is larger than the sum of its proper divisors (1016511227).

1987391493 is a wasteful number, since it uses less digits than its factorization.

1987391493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97689 (or 97686 counting only the distinct ones).

The product of its digits is 1469664, while the sum is 54.

The square root of 1987391493 is about 44580.1692796248. The cubic root of 1987391493 is about 1257.2678460064.

The spelling of 1987391493 in words is "one billion, nine hundred eighty-seven million, three hundred ninety-one thousand, four hundred ninety-three".