1261396749 has 8 divisors (see below), whose sum is σ = 1682093952. Its totient is φ = 840815360.

The previous prime is 1261396709. The next prime is 1261396811. The reversal of 1261396749 is 9476931621.

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 1261396749 - 2⁷ = 1261396621 is a prime.

It is a super-2 number, since 2×1261396749² = 3182243516775538002, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1261396698 and 1261396707.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261396709) 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, 844 + ... + 50234.

It is an arithmetic number, because the mean of its divisors is an integer number (210261744).

Almost surely, 2^1261396749 is an apocalyptic number.

It is an amenable number.

1261396749 is a deficient number, since it is larger than the sum of its proper divisors (420697203).

1261396749 is an equidigital number, since it uses as much as digits as its factorization.

1261396749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57907.

The product of its digits is 489888, while the sum is 48.

The square root of 1261396749 is about 35516.1477218462. The cubic root of 1261396749 is about 1080.4812524268.

The spelling of 1261396749 in words is "one billion, two hundred sixty-one million, three hundred ninety-six thousand, seven hundred forty-nine".