1289431872 has 196 divisors, whose sum is σ = 3972770820. Its totient is φ = 414554112.

The previous prime is 1289431867. The next prime is 1289431879. The reversal of 1289431872 is 2781349821.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 606341376 + 683090496 = 24624^2 + 26136^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1289431879) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 1352548 + ... + 1353500.

Almost surely, 2^1289431872 is an apocalyptic number.

1289431872 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1289431872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1986385410).

1289431872 is an abundant number, since it is smaller than the sum of its proper divisors (2683338948).

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

1289431872 is an frugal number, since it uses more digits than its factorization.

1289431872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1012 (or 987 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 1289431872 is about 35908.6601253792. The cubic root of 1289431872 is about 1088.4274020055.

The spelling of 1289431872 in words is "one billion, two hundred eighty-nine million, four hundred thirty-one thousand, eight hundred seventy-two".