1987778 has 12 divisors (see below), whose sum is σ = 3229218. Its totient is φ = 917280.

The previous prime is 1987709. The next prime is 1987789. The reversal of 1987778 is 8777891.

It can be written as a sum of positive squares in 3 ways, for example, as 1352569 + 635209 = 1163^2 + 797^2 .

It is a super-2 number, since 2×1987778² = 7902522754568, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2603 + ... + 3278.

2^1987778 is an apocalyptic number.

1987778 is a deficient number, since it is larger than the sum of its proper divisors (1241440).

1987778 is a wasteful number, since it uses less digits than its factorization.

1987778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5909 (or 5896 counting only the distinct ones).

The product of its digits is 197568, while the sum is 47.

The square root of 1987778 is about 1409.8858109790. The cubic root of 1987778 is about 125.7349345018.

The spelling of 1987778 in words is "one million, nine hundred eighty-seven thousand, seven hundred seventy-eight".