1231217720 has 16 divisors (see below), whose sum is σ = 2770239960. Its totient is φ = 492487072.

The previous prime is 1231217699. The next prime is 1231217759. The reversal of 1231217720 is 277121321.

It is a self number, because there is not a number n which added to its sum of digits gives 1231217720.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15390182 + ... + 15390261.

Almost surely, 2^1231217720 is an apocalyptic number.

1231217720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1231217720 is an abundant number, since it is smaller than the sum of its proper divisors (1539022240).

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

1231217720 is a wasteful number, since it uses less digits than its factorization.

1231217720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30780454 (or 30780450 counting only the distinct ones).

The product of its (nonzero) digits is 1176, while the sum is 26.

The square root of 1231217720 is about 35088.7121450759. The cubic root of 1231217720 is about 1071.7947344974.

The spelling of 1231217720 in words is "one billion, two hundred thirty-one million, two hundred seventeen thousand, seven hundred twenty".