1217145985 has 32 divisors (see below), whose sum is σ = 1688688000. Its totient is φ = 832872960.

The previous prime is 1217145983. The next prime is 1217146001. The reversal of 1217145985 is 5895417121.

It is not a de Polignac number, because 1217145985 - 2¹ = 1217145983 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1217145983) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 151797 + ... + 159613.

It is an arithmetic number, because the mean of its divisors is an integer number (52771500).

Almost surely, 2^1217145985 is an apocalyptic number.

It is an amenable number.

1217145985 is a deficient number, since it is larger than the sum of its proper divisors (471542015).

1217145985 is a wasteful number, since it uses less digits than its factorization.

1217145985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8001.

The product of its digits is 100800, while the sum is 43.

The square root of 1217145985 is about 34887.6193656145. The cubic root of 1217145985 is about 1067.6958555568.

The spelling of 1217145985 in words is "one billion, two hundred seventeen million, one hundred forty-five thousand, nine hundred eighty-five".