1289981772 has 36 divisors (see below), whose sum is σ = 3402562800. Its totient is φ = 411298272.

The previous prime is 1289981761. The next prime is 1289981779. The reversal of 1289981772 is 2771899821.

It is a tau number, because it is divible by the number of its divisors (36).

It is not an unprimeable number, because it can be changed into a prime (1289981779) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 778147 + ... + 779802.

Almost surely, 2^1289981772 is an apocalyptic number.

1289981772 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1289981772 is an abundant number, since it is smaller than the sum of its proper divisors (2112581028).

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

1289981772 is a wasteful number, since it uses less digits than its factorization.

1289981772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1557982 (or 1557977 counting only the distinct ones).

The product of its digits is 1016064, while the sum is 54.

The square root of 1289981772 is about 35916.3162364962. The cubic root of 1289981772 is about 1088.5821060985.

The spelling of 1289981772 in words is "one billion, two hundred eighty-nine million, nine hundred eighty-one thousand, seven hundred seventy-two".