21063667 has 4 divisors (see below), whose sum is σ = 21079800. Its totient is φ = 21047536.

The previous prime is 21063569. The next prime is 21063673. The reversal of 21063667 is 76636012.

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

It is a cyclic number.

It is not a de Polignac number, because 21063667 - 2¹¹ = 21061619 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21003667) 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, 5917 + ... + 8782.

It is an arithmetic number, because the mean of its divisors is an integer number (5269950).

Almost surely, 2^21063667 is an apocalyptic number.

21063667 is a deficient number, since it is larger than the sum of its proper divisors (16133).

21063667 is a wasteful number, since it uses less digits than its factorization.

21063667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16132.

The product of its (nonzero) digits is 9072, while the sum is 31.

The square root of 21063667 is about 4589.5170769919. The cubic root of 21063667 is about 276.1709497203.

Adding to 21063667 its reverse (76636012), we get a palindrome (97699679).

The spelling of 21063667 in words is "twenty-one million, sixty-three thousand, six hundred sixty-seven".