1261999 has 8 divisors (see below), whose sum is σ = 1341440. Its totient is φ = 1183896.

The previous prime is 1261973. The next prime is 1262011. The reversal of 1261999 is 9991621.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1261999 - 2⁹ = 1261487 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261969) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2152 + ... + 2674.

It is an arithmetic number, because the mean of its divisors is an integer number (167680).

2^1261999 is an apocalyptic number.

1261999 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

1261999 is a deficient number, since it is larger than the sum of its proper divisors (79441).

1261999 is a wasteful number, since it uses less digits than its factorization.

1261999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 669.

The product of its digits is 8748, while the sum is 37.

The square root of 1261999 is about 1123.3872885163. The cubic root of 1261999 is about 108.0653182837.

The spelling of 1261999 in words is "one million, two hundred sixty-one thousand, nine hundred ninety-nine".