21264587 has 2 divisors, whose sum is σ = 21264588. Its totient is φ = 21264586.

The previous prime is 21264583. The next prime is 21264601. The reversal of 21264587 is 78546212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21264587 - 2² = 21264583 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21264583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10632293 + 10632294.

It is an arithmetic number, because the mean of its divisors is an integer number (10632294).

Almost surely, 2^21264587 is an apocalyptic number.

21264587 is a deficient number, since it is larger than the sum of its proper divisors (1).

21264587 is an equidigital number, since it uses as much as digits as its factorization.

21264587 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26880, while the sum is 35.

The square root of 21264587 is about 4611.3541395126. The cubic root of 21264587 is about 277.0462763766.

The spelling of 21264587 in words is "twenty-one million, two hundred sixty-four thousand, five hundred eighty-seven".