289991661 has 32 divisors (see below), whose sum is σ = 432662400. Its totient is φ = 172171008.

The previous prime is 289991657. The next prime is 289991693. The reversal of 289991661 is 166199982.

It is not a de Polignac number, because 289991661 - 2² = 289991657 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (289991641) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 349395 + ... + 350223.

It is an arithmetic number, because the mean of its divisors is an integer number (13520700).

Almost surely, 2^289991661 is an apocalyptic number.

It is an amenable number.

289991661 is a deficient number, since it is larger than the sum of its proper divisors (142670739).

289991661 is an equidigital number, since it uses as much as digits as its factorization.

289991661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 906 (or 868 counting only the distinct ones).

The product of its digits is 419904, while the sum is 51.

The square root of 289991661 is about 17029.1415226957. The cubic root of 289991661 is about 661.9042502907.

The spelling of 289991661 in words is "two hundred eighty-nine million, nine hundred ninety-one thousand, six hundred sixty-one".