1261681 has 4 divisors (see below), whose sum is σ = 1267200. Its totient is φ = 1256164.

The previous prime is 1261649. The next prime is 1261697. The reversal of 1261681 is 1861621.

1261681 is nontrivially palindromic in base 4.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1261681 - 2⁵ = 1261649 is a prime.

It is a super-2 number, since 2×1261681² = 3183677891522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1261081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2401 + ... + 2878.

It is an arithmetic number, because the mean of its divisors is an integer number (316800).

2^1261681 is an apocalyptic number.

It is an amenable number.

1261681 is a deficient number, since it is larger than the sum of its proper divisors (5519).

1261681 is an equidigital number, since it uses as much as digits as its factorization.

1261681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5518.

The product of its digits is 576, while the sum is 25.

The square root of 1261681 is about 1123.2457433705. The cubic root of 1261681 is about 108.0562407123.

The spelling of 1261681 in words is "one million, two hundred sixty-one thousand, six hundred eighty-one".