21650369 has 12 divisors (see below), whose sum is σ = 24106068. Its totient is φ = 19329120.

The previous prime is 21650351. The next prime is 21650389. The reversal of 21650369 is 96305612.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 6150400 + 15499969 = 2480^2 + 3937^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21650369 is a prime.

It is a super-2 number, since 2×21650369² = 937476955672322, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21650339) 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, 11627 + ... + 13359.

It is an arithmetic number, because the mean of its divisors is an integer number (2008839).

Almost surely, 2^21650369 is an apocalyptic number.

It is an amenable number.

21650369 is a deficient number, since it is larger than the sum of its proper divisors (2455699).

21650369 is a wasteful number, since it uses less digits than its factorization.

21650369 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1808 (or 1777 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 32.

The square root of 21650369 is about 4652.9957016958. The cubic root of 21650369 is about 278.7116362172.

The spelling of 21650369 in words is "twenty-one million, six hundred fifty thousand, three hundred sixty-nine".