1218831901 has 4 divisors (see below), whose sum is σ = 1392950752. Its totient is φ = 1044713052.

The previous prime is 1218831877. The next prime is 1218831959. The reversal of 1218831901 is 1091388121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1218831901 - 2⁹ = 1218831389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1218891901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87059415 + ... + 87059428.

It is an arithmetic number, because the mean of its divisors is an integer number (348237688).

Almost surely, 2^1218831901 is an apocalyptic number.

It is an amenable number.

1218831901 is a deficient number, since it is larger than the sum of its proper divisors (174118851).

1218831901 is an equidigital number, since it uses as much as digits as its factorization.

1218831901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174118850.

The product of its (nonzero) digits is 3456, while the sum is 34.

The square root of 1218831901 is about 34911.7731002022. The cubic root of 1218831901 is about 1068.1885970693.

The spelling of 1218831901 in words is "one billion, two hundred eighteen million, eight hundred thirty-one thousand, nine hundred one".