21128967 has 6 divisors (see below), whose sum is σ = 30519632. Its totient is φ = 14085972.

The previous prime is 21128959. The next prime is 21128971. The reversal of 21128967 is 76982112.

It is not a de Polignac number, because 21128967 - 2³ = 21128959 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21128917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1173823 + ... + 1173840.

Almost surely, 2^21128967 is an apocalyptic number.

21128967 is a deficient number, since it is larger than the sum of its proper divisors (9390665).

21128967 is a wasteful number, since it uses less digits than its factorization.

21128967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2347669 (or 2347666 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 21128967 is about 4596.6256101623. The cubic root of 21128967 is about 276.4560434665.

The spelling of 21128967 in words is "twenty-one million, one hundred twenty-eight thousand, nine hundred sixty-seven".