21428967 has 16 divisors (see below), whose sum is σ = 33708032. Its totient is φ = 11849760.

The previous prime is 21428963. The next prime is 21428969. The reversal of 21428967 is 76982412.

It is not a de Polignac number, because 21428967 - 2² = 21428963 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 (21428963) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15808 + ... + 17109.

It is an arithmetic number, because the mean of its divisors is an integer number (2106752).

Almost surely, 2^21428967 is an apocalyptic number.

21428967 is a deficient number, since it is larger than the sum of its proper divisors (12279065).

21428967 is a wasteful number, since it uses less digits than its factorization.

21428967 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32958.

The product of its digits is 48384, while the sum is 39.

The square root of 21428967 is about 4629.1432252632. The cubic root of 21428967 is about 277.7583212624.

The spelling of 21428967 in words is "twenty-one million, four hundred twenty-eight thousand, nine hundred sixty-seven".