21326667 has 16 divisors (see below), whose sum is σ = 30041088. Its totient is φ = 13436640.

The previous prime is 21326663. The next prime is 21326699. The reversal of 21326667 is 76662312.

It is not a de Polignac number, because 21326667 - 2² = 21326663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21326663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1333 + ... + 6665.

It is an arithmetic number, because the mean of its divisors is an integer number (1877568).

Almost surely, 2^21326667 is an apocalyptic number.

21326667 is a deficient number, since it is larger than the sum of its proper divisors (8714421).

21326667 is a wasteful number, since it uses less digits than its factorization.

21326667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5410.

The product of its digits is 18144, while the sum is 33.

The square root of 21326667 is about 4618.0804453799. The cubic root of 21326667 is about 277.3156181221.

Adding to 21326667 its reverse (76662312), we get a palindrome (97988979).

The spelling of 21326667 in words is "twenty-one million, three hundred twenty-six thousand, six hundred sixty-seven".