1261777740 has 48 divisors (see below), whose sum is σ = 3740802912. Its totient is φ = 316681216.

The previous prime is 1261777739. The next prime is 1261777789. The reversal of 1261777740 is 477771621.

It is a junction number, because it is equal to n+sod(n) for n = 1261777692 and 1261777701.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 617499 + ... + 619538.

It is an arithmetic number, because the mean of its divisors is an integer number (77933394).

Almost surely, 2^1261777740 is an apocalyptic number.

1261777740 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1261777740 is an abundant number, since it is smaller than the sum of its proper divisors (2479025172).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1261777740 is a wasteful number, since it uses less digits than its factorization.

1261777740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1237066 (or 1237064 counting only the distinct ones).

The product of its (nonzero) digits is 115248, while the sum is 42.

The square root of 1261777740 is about 35521.5109475934. The cubic root of 1261777740 is about 1080.5900239652.

The spelling of 1261777740 in words is "one billion, two hundred sixty-one million, seven hundred seventy-seven thousand, seven hundred forty".