1213439989 has 4 divisors (see below), whose sum is σ = 1213513056. Its totient is φ = 1213366924.

The previous prime is 1213439951. The next prime is 1213440023. The reversal of 1213439989 is 9899343121.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 1213439989 - 2¹⁷ = 1213308917 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 (1213439939) 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, 1752 + ... + 49294.

It is an arithmetic number, because the mean of its divisors is an integer number (303378264).

Almost surely, 2^1213439989 is an apocalyptic number.

It is an amenable number.

1213439989 is a deficient number, since it is larger than the sum of its proper divisors (73067).

1213439989 is an equidigital number, since it uses as much as digits as its factorization.

1213439989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73066.

The product of its digits is 419904, while the sum is 49.

The square root of 1213439989 is about 34834.4655334340. The cubic root of 1213439989 is about 1066.6111049943.

The spelling of 1213439989 in words is "one billion, two hundred thirteen million, four hundred thirty-nine thousand, nine hundred eighty-nine".