21669026 has 8 divisors (see below), whose sum is σ = 32625180. Its totient is φ = 10793968.

The previous prime is 21669019. The next prime is 21669029. The reversal of 21669026 is 62096612.

It is a Cunningham number, because it is equal to 4655²+1.

It can be written as a sum of positive squares in 2 ways, for example, as 21669025 + 1 = 4655^2 + 1^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 21668983 and 21669001.

It is not an unprimeable number, because it can be changed into a prime (21669029) 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, 19601 + ... + 20676.

Almost surely, 2^21669026 is an apocalyptic number.

21669026 is a deficient number, since it is larger than the sum of its proper divisors (10956154).

21669026 is a wasteful number, since it uses less digits than its factorization.

21669026 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40548.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 21669026 is about 4655.0001074114. Note that the first 3 decimals coincide. The cubic root of 21669026 is about 278.7916722673.

The spelling of 21669026 in words is "twenty-one million, six hundred sixty-nine thousand, twenty-six".