20287969 has 8 divisors (see below), whose sum is σ = 21915432. Its totient is φ = 18670080.

The previous prime is 20287961. The next prime is 20287997. The reversal of 20287969 is 96978202.

20287969 = 41² + 42² + ... + 393².

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2140369 + 18147600 = 1463^2 + 4260^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20287969 - 2³ = 20287961 is a prime.

It is a super-2 number, since 2×20287969² = 823203372289922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20287961) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2379 + ... + 6799.

It is an arithmetic number, because the mean of its divisors is an integer number (2739429).

Almost surely, 2^20287969 is an apocalyptic number.

It is an amenable number.

20287969 is a deficient number, since it is larger than the sum of its proper divisors (1627463).

20287969 is a wasteful number, since it uses less digits than its factorization.

20287969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4787.

The product of its (nonzero) digits is 108864, while the sum is 43.

The square root of 20287969 is about 4504.2168020645. The cubic root of 20287969 is about 272.7383387395.

The spelling of 20287969 in words is "twenty million, two hundred eighty-seven thousand, nine hundred sixty-nine".