1291640156 has 12 divisors (see below), whose sum is σ = 2264098368. Its totient is φ = 644754912.

The previous prime is 1291640143. The next prime is 1291640167. The reversal of 1291640156 is 6510461921.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 263561 + ... + 268416.

It is an arithmetic number, because the mean of its divisors is an integer number (188674864).

Almost surely, 2^1291640156 is an apocalyptic number.

It is an amenable number.

1291640156 is a deficient number, since it is larger than the sum of its proper divisors (972458212).

1291640156 is a wasteful number, since it uses less digits than its factorization.

1291640156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 532588 (or 532586 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 35.

The square root of 1291640156 is about 35939.3955987020. The cubic root of 1291640156 is about 1089.0483953957.

The spelling of 1291640156 in words is "one billion, two hundred ninety-one million, six hundred forty thousand, one hundred fifty-six".