1987211799225 has 27 divisors (see below), whose sum is σ = 3559355007663. Its totient is φ = 1059835015440.

The previous prime is 1987211799187. The next prime is 1987211799239. The reversal of 1987211799225 is 5229971127891.

The square root of 1987211799225 is 1409685.

It is a perfect power (a square), and thus also a powerful number.

1987211799225 is a `hidden beast` number, since 198 + 7 + 211 + 7 + 9 + 9 + 225 = 666.

It can be written as a sum of positive squares in only one way, i.e., 715396247721 + 1271815551504 = 845811^2 + 1127748^2 .

It is not a de Polignac number, because 1987211799225 - 2³⁵ = 1952852060857 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 21098286 + ... + 21192264.

Almost surely, 2^{1987211799225} is an apocalyptic number.

1987211799225 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1987211799225 is the 1409685-th square number.

1987211799225 is the 704843-rd centered octagonal number.

It is an amenable number.

1987211799225 is a deficient number, since it is larger than the sum of its proper divisors (1572143208438).

1987211799225 is an frugal number, since it uses more digits than its factorization.

1987211799225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187974 (or 93987 counting only the distinct ones).

The product of its digits is 11430720, while the sum is 63.

The spelling of 1987211799225 in words is "one trillion, nine hundred eighty-seven billion, two hundred eleven million, seven hundred ninety-nine thousand, two hundred twenty-five".