21277066 has 4 divisors (see below), whose sum is σ = 31915602. Its totient is φ = 10638532.

The previous prime is 21277063. The next prime is 21277117. The reversal of 21277066 is 66077212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 14100025 + 7177041 = 3755^2 + 2679^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21277063) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5319265 + ... + 5319268.

Almost surely, 2^21277066 is an apocalyptic number.

21277066 is a deficient number, since it is larger than the sum of its proper divisors (10638536).

21277066 is a wasteful number, since it uses less digits than its factorization.

21277066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10638535.

The product of its (nonzero) digits is 7056, while the sum is 31.

The square root of 21277066 is about 4612.7070143247. The cubic root of 21277066 is about 277.1004601143.

The spelling of 21277066 in words is "twenty-one million, two hundred seventy-seven thousand, sixty-six".