1261391 has 8 divisors (see below), whose sum is σ = 1338480. Its totient is φ = 1185408.

The previous prime is 1261387. The next prime is 1261411. The reversal of 1261391 is 1931621.

It is a happy number.

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 1261391 - 2² = 1261387 is a prime.

It is a super-2 number, since 2×1261391² = 3182214509762, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261301) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3575 + ... + 3911.

It is an arithmetic number, because the mean of its divisors is an integer number (167310).

2^1261391 is an apocalyptic number.

1261391 is a deficient number, since it is larger than the sum of its proper divisors (77089).

1261391 is a wasteful number, since it uses less digits than its factorization.

1261391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 553.

The product of its digits is 324, while the sum is 23.

The square root of 1261391 is about 1123.1166457675. The cubic root of 1261391 is about 108.0479610941.

The spelling of 1261391 in words is "one million, two hundred sixty-one thousand, three hundred ninety-one".