21367487 has 4 divisors (see below), whose sum is σ = 22624416. Its totient is φ = 20110560.

The previous prime is 21367481. The next prime is 21367501. The reversal of 21367487 is 78476312.

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 21367487 - 2¹⁰ = 21366463 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21367487.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21367481) 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 3 ways as a sum of consecutive naturals, for example, 628439 + ... + 628472.

It is an arithmetic number, because the mean of its divisors is an integer number (5656104).

Almost surely, 2^21367487 is an apocalyptic number.

21367487 is a deficient number, since it is larger than the sum of its proper divisors (1256929).

21367487 is a wasteful number, since it uses less digits than its factorization.

21367487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1256928.

The product of its digits is 56448, while the sum is 38.

The square root of 21367487 is about 4622.4979177929. The cubic root of 21367487 is about 277.4924360138.

The spelling of 21367487 in words is "twenty-one million, three hundred sixty-seven thousand, four hundred eighty-seven".