1291905 has 24 divisors (see below), whose sum is σ = 2358720. Its totient is φ = 652320.

The previous prime is 1291883. The next prime is 1291907. The reversal of 1291905 is 5091921.

It is a happy number.

It is not a de Polignac number, because 1291905 - 2¹⁹ = 767617 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1291907) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 100 + ... + 1610.

It is an arithmetic number, because the mean of its divisors is an integer number (98280).

2^1291905 is an apocalyptic number.

1291905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1291905 is a deficient number, since it is larger than the sum of its proper divisors (1066815).

1291905 is a wasteful number, since it uses less digits than its factorization.

1291905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1541 (or 1538 counting only the distinct ones).

The product of its (nonzero) digits is 810, while the sum is 27.

The square root of 1291905 is about 1136.6199892664. The cubic root of 1291905 is about 108.9122824852.

The spelling of 1291905 in words is "one million, two hundred ninety-one thousand, nine hundred five".