1291890 has 16 divisors (see below), whose sum is σ = 3100608. Its totient is φ = 344496.

The previous prime is 1291883. The next prime is 1291907. The reversal of 1291890 is 981921.

It is a super-3 number, since 3×1291890³ = 6468414833334807000, which contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 43063 = 1291890 / (1 + 2 + 9 + 1 + 8 + 9 + 0).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21502 + ... + 21561.

It is an arithmetic number, because the mean of its divisors is an integer number (193788).

2^1291890 is an apocalyptic number.

1291890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1291890 is an abundant number, since it is smaller than the sum of its proper divisors (1808718).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1291890 is a wasteful number, since it uses less digits than its factorization.

1291890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43073.

The product of its (nonzero) digits is 1296, while the sum is 30.

The square root of 1291890 is about 1136.6133907358. The cubic root of 1291890 is about 108.9118609654.

The spelling of 1291890 in words is "one million, two hundred ninety-one thousand, eight hundred ninety".