1291635138 has 16 divisors (see below), whose sum is σ = 2588807520. Its totient is φ = 429622176.

The previous prime is 1291635113. The next prime is 1291635193. The reversal of 1291635138 is 8315361921.

It is a junction number, because it is equal to n+sod(n) for n = 1291635096 and 1291635105.

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, 227683 + ... + 233286.

It is an arithmetic number, because the mean of its divisors is an integer number (161800470).

Almost surely, 2^1291635138 is an apocalyptic number.

1291635138 is an abundant number, since it is smaller than the sum of its proper divisors (1297172382).

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

1291635138 is a wasteful number, since it uses less digits than its factorization.

1291635138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 461441.

The product of its digits is 38880, while the sum is 39.

The square root of 1291635138 is about 35939.3257866644. The cubic root of 1291635138 is about 1089.0469850824.

The spelling of 1291635138 in words is "one billion, two hundred ninety-one million, six hundred thirty-five thousand, one hundred thirty-eight".