21887369 has 12 divisors (see below), whose sum is σ = 25545348. Its totient is φ = 18698400.

The previous prime is 21887353. The next prime is 21887377. The reversal of 21887369 is 96378812.

It can be written as a sum of positive squares in 2 ways, for example, as 5175625 + 16711744 = 2275^2 + 4088^2 .

It is not a de Polignac number, because 21887369 - 2⁴ = 21887353 is a prime.

It is a super-2 number, since 2×21887369² = 958113843484322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21887339) 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, 20099 + ... + 21159.

It is an arithmetic number, because the mean of its divisors is an integer number (2128779).

Almost surely, 2^21887369 is an apocalyptic number.

It is an amenable number.

21887369 is a deficient number, since it is larger than the sum of its proper divisors (3657979).

21887369 is a wasteful number, since it uses less digits than its factorization.

21887369 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1496 (or 1489 counting only the distinct ones).

The product of its digits is 145152, while the sum is 44.

The square root of 21887369 is about 4678.3938483202. The cubic root of 21887369 is about 279.7249382111.

The spelling of 21887369 in words is "twenty-one million, eight hundred eighty-seven thousand, three hundred sixty-nine".