1987409905 has 64 divisors (see below), whose sum is σ = 2811207168. Its totient is φ = 1335398400.

The previous prime is 1987409903. The next prime is 1987409909. The reversal of 1987409905 is 5099047891.

It is not a de Polignac number, because 1987409905 - 2¹ = 1987409903 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1987409903) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 7174627 + ... + 7174903.

It is an arithmetic number, because the mean of its divisors is an integer number (43925112).

Almost surely, 2^1987409905 is an apocalyptic number.

It is an amenable number.

1987409905 is a deficient number, since it is larger than the sum of its proper divisors (823797263).

1987409905 is a wasteful number, since it uses less digits than its factorization.

1987409905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 506.

The product of its (nonzero) digits is 816480, while the sum is 52.

The square root of 1987409905 is about 44580.3757835216. The cubic root of 1987409905 is about 1257.2717286073.

The spelling of 1987409905 in words is "one billion, nine hundred eighty-seven million, four hundred nine thousand, nine hundred five".