1987972551 has 12 divisors (see below), whose sum is σ = 2977868712. Its totient is φ = 1325314872.

The previous prime is 1987972541. The next prime is 1987972561. The reversal of 1987972551 is 1552797891.

1987972551 is a `hidden beast` number, since 1 + 9 + 87 + 9 + 7 + 2 + 551 = 666.

It is an interprime number because it is at equal distance from previous prime (1987972541) and next prime (1987972561).

It is not a de Polignac number, because 1987972551 - 2⁶ = 1987972487 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1987972541) 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 11 ways as a sum of consecutive naturals, for example, 4090236 + ... + 4090721.

It is an arithmetic number, because the mean of its divisors is an integer number (248155726).

Almost surely, 2^1987972551 is an apocalyptic number.

1987972551 is a deficient number, since it is larger than the sum of its proper divisors (989896161).

1987972551 is an frugal number, since it uses more digits than its factorization.

1987972551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8180972 (or 8180960 counting only the distinct ones).

The product of its digits is 1587600, while the sum is 54.

The square root of 1987972551 is about 44586.6858041725. The cubic root of 1987972551 is about 1257.3903641174.

The spelling of 1987972551 in words is "one billion, nine hundred eighty-seven million, nine hundred seventy-two thousand, five hundred fifty-one".