1291920680 has 16 divisors (see below), whose sum is σ = 2906821620. Its totient is φ = 516768256.

The previous prime is 1291920677. The next prime is 1291920683. The reversal of 1291920680 is 860291921.

It is an interprime number because it is at equal distance from previous prime (1291920677) and next prime (1291920683).

It can be written as a sum of positive squares in 2 ways, for example, as 1216195876 + 75724804 = 34874^2 + 8702^2 .

It is not an unprimeable number, because it can be changed into a prime (1291920683) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16148969 + ... + 16149048.

Almost surely, 2^1291920680 is an apocalyptic number.

1291920680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1291920680 is an abundant number, since it is smaller than the sum of its proper divisors (1614900940).

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

1291920680 is a wasteful number, since it uses less digits than its factorization.

1291920680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32298028 (or 32298024 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 1291920680 is about 35943.2981235724. The cubic root of 1291920680 is about 1089.1272311035.

The spelling of 1291920680 in words is "one billion, two hundred ninety-one million, nine hundred twenty thousand, six hundred eighty".