1217831638 has 16 divisors (see below), whose sum is σ = 1967613120. Its totient is φ = 563451336.

The previous prime is 1217831627. The next prime is 1217831663. The reversal of 1217831638 is 8361387121.

It is a super-2 number, since 2×1217831638² = 2966227797027526088, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1217831638.

It is a congruent number.

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, 371020 + ... + 374287.

It is an arithmetic number, because the mean of its divisors is an integer number (122975820).

Almost surely, 2^1217831638 is an apocalyptic number.

1217831638 is a deficient number, since it is larger than the sum of its proper divisors (749781482).

1217831638 is a wasteful number, since it uses less digits than its factorization.

1217831638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 745371.

The product of its digits is 48384, while the sum is 40.

The square root of 1217831638 is about 34897.4445769314. Note that the first 3 decimals coincide. The cubic root of 1217831638 is about 1067.8963057502.

The spelling of 1217831638 in words is "one billion, two hundred seventeen million, eight hundred thirty-one thousand, six hundred thirty-eight".