1987745701 has 4 divisors (see below), whose sum is σ = 1988001900. Its totient is φ = 1987489504.

The previous prime is 1987745681. The next prime is 1987745719. The reversal of 1987745701 is 1075477891.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 725009476 + 1262736225 = 26926^2 + 35535^2 .

It is a cyclic number.

It is not a de Polignac number, because 1987745701 - 2⁹ = 1987745189 is a prime.

It is a super-2 number, since 2×1987745701² = 7902265943687962802, which contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1987745101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 116086 + ... + 132103.

It is an arithmetic number, because the mean of its divisors is an integer number (497000475).

Almost surely, 2^1987745701 is an apocalyptic number.

It is an amenable number.

1987745701 is a deficient number, since it is larger than the sum of its proper divisors (256199).

1987745701 is an equidigital number, since it uses as much as digits as its factorization.

1987745701 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 256198.

The product of its (nonzero) digits is 493920, while the sum is 49.

The square root of 1987745701 is about 44584.1418107380. The cubic root of 1987745701 is about 1257.3425348429.

The spelling of 1987745701 in words is "one billion, nine hundred eighty-seven million, seven hundred forty-five thousand, seven hundred one".