1291020940 has 24 divisors (see below), whose sum is σ = 2957612112. Its totient is φ = 469462080.

The previous prime is 1291020931. The next prime is 1291020967. The reversal of 1291020940 is 490201921.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 1291020899 and 1291020908.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2933919 + ... + 2934358.

It is an arithmetic number, because the mean of its divisors is an integer number (123233838).

Almost surely, 2^1291020940 is an apocalyptic number.

1291020940 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1291020940 is an abundant number, since it is smaller than the sum of its proper divisors (1666591172).

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

1291020940 is a wasteful number, since it uses less digits than its factorization.

1291020940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5868297 (or 5868295 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 1291020940 is about 35930.7798412447. The cubic root of 1291020940 is about 1088.8743366019.

The spelling of 1291020940 in words is "one billion, two hundred ninety-one million, twenty thousand, nine hundred forty".