1917988 has 6 divisors (see below), whose sum is σ = 3356486. Its totient is φ = 958992.

The previous prime is 1917977. The next prime is 1918003. The reversal of 1917988 is 8897191.

It can be written as a sum of positive squares in only one way, i.e., 1695204 + 222784 = 1302^2 + 472^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 239745 + ... + 239752.

2^1917988 is an apocalyptic number.

It is an amenable number.

1917988 is a deficient number, since it is larger than the sum of its proper divisors (1438498).

1917988 is a wasteful number, since it uses less digits than its factorization.

1917988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 479501 (or 479499 counting only the distinct ones).

The product of its digits is 36288, while the sum is 43.

The square root of 1917988 is about 1384.9144377903. The cubic root of 1917988 is about 124.2458701212.

The spelling of 1917988 in words is "one million, nine hundred seventeen thousand, nine hundred eighty-eight".