245691989 has 4 divisors (see below), whose sum is σ = 249856320. Its totient is φ = 241527660.

The previous prime is 245691961. The next prime is 245691991. The reversal of 245691989 is 989196542.

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 245691989 - 2²⁴ = 228914773 is a prime.

It is a super-2 number, since 2×245691989² = 120729106917552242, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 245691989.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (245691289) 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, 2082077 + ... + 2082194.

It is an arithmetic number, because the mean of its divisors is an integer number (62464080).

Almost surely, 2^245691989 is an apocalyptic number.

It is an amenable number.

245691989 is a deficient number, since it is larger than the sum of its proper divisors (4164331).

245691989 is an equidigital number, since it uses as much as digits as its factorization.

245691989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4164330.

The product of its digits is 1399680, while the sum is 53.

The square root of 245691989 is about 15674.5650338375. The cubic root of 245691989 is about 626.3210364265.

The spelling of 245691989 in words is "two hundred forty-five million, six hundred ninety-one thousand, nine hundred eighty-nine".