21069028 has 6 divisors (see below), whose sum is σ = 36870806. Its totient is φ = 10534512.

The previous prime is 21069023. The next prime is 21069031. The reversal of 21069028 is 82096012.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 10969344 + 10099684 = 3312^2 + 3178^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21068987 and 21069005.

It is not an unprimeable number, because it can be changed into a prime (21069023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2633625 + ... + 2633632.

Almost surely, 2^21069028 is an apocalyptic number.

It is an amenable number.

21069028 is a deficient number, since it is larger than the sum of its proper divisors (15801778).

21069028 is a wasteful number, since it uses less digits than its factorization.

21069028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5267261 (or 5267259 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 21069028 is about 4590.1010882115. The cubic root of 21069028 is about 276.1943775320.

The spelling of 21069028 in words is "twenty-one million, sixty-nine thousand, twenty-eight".