1249311681 has 20 divisors (see below), whose sum is σ = 1894118512. Its totient is φ = 820439928.

The previous prime is 1249311649. The next prime is 1249311689. The reversal of 1249311681 is 1861139421.

1249311681 is a `hidden beast` number, since 1 + 2 + 493 + 1 + 168 + 1 = 666.

It is not a de Polignac number, because 1249311681 - 2⁵ = 1249311649 is a prime.

It is a super-2 number, since 2×1249311681² = 3121559352566091522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1249311689) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 109675 + ... + 120528.

Almost surely, 2^1249311681 is an apocalyptic number.

It is an amenable number.

1249311681 is a deficient number, since it is larger than the sum of its proper divisors (644806831).

1249311681 is an equidigital number, since it uses as much as digits as its factorization.

1249311681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230282 (or 230273 counting only the distinct ones).

The product of its digits is 10368, while the sum is 36.

The square root of 1249311681 is about 35345.6034182471. The cubic root of 1249311681 is about 1077.0195836012.

The spelling of 1249311681 in words is "one billion, two hundred forty-nine million, three hundred eleven thousand, six hundred eighty-one".