1291988 has 6 divisors (see below), whose sum is σ = 2260986. Its totient is φ = 645992.

The previous prime is 1291967. The next prime is 1291991. The reversal of 1291988 is 8891921.

It can be written as a sum of positive squares in only one way, i.e., 976144 + 315844 = 988^2 + 562^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161495 + ... + 161502.

It is an arithmetic number, because the mean of its divisors is an integer number (376831).

2^1291988 is an apocalyptic number.

It is an amenable number.

1291988 is a deficient number, since it is larger than the sum of its proper divisors (968998).

1291988 is a wasteful number, since it uses less digits than its factorization.

1291988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323001 (or 322999 counting only the distinct ones).

The product of its digits is 10368, while the sum is 38.

The square root of 1291988 is about 1136.6565004433. The cubic root of 1291988 is about 108.9146148357.

The spelling of 1291988 in words is "one million, two hundred ninety-one thousand, nine hundred eighty-eight".