1291391390 has 24 divisors (see below), whose sum is σ = 2389052232. Its totient is φ = 502590240.

The previous prime is 1291391369. The next prime is 1291391393. The reversal of 1291391390 is 931931921.

It is a super-2 number, since 2×1291391390² = 3335383444332264200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291391393) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 33476 + ... + 60855.

It is an arithmetic number, because the mean of its divisors is an integer number (99543843).

Almost surely, 2^1291391390 is an apocalyptic number.

1291391390 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1291391390 is a deficient number, since it is larger than the sum of its proper divisors (1097660842).

1291391390 is an equidigital number, since it uses as much as digits as its factorization.

1291391390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94412 (or 94375 counting only the distinct ones).

The product of its (nonzero) digits is 13122, while the sum is 38.

The square root of 1291391390 is about 35935.9345224248. The cubic root of 1291391390 is about 1088.9784750941.

The spelling of 1291391390 in words is "one billion, two hundred ninety-one million, three hundred ninety-one thousand, three hundred ninety".