21374587 has 4 divisors (see below), whose sum is σ = 23018800. Its totient is φ = 19730376.

The previous prime is 21374543. The next prime is 21374597. The reversal of 21374587 is 78547312.

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 21374587 - 2⁷ = 21374459 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21374597) 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, 822087 + ... + 822112.

It is an arithmetic number, because the mean of its divisors is an integer number (5754700).

Almost surely, 2^21374587 is an apocalyptic number.

21374587 is a deficient number, since it is larger than the sum of its proper divisors (1644213).

21374587 is a wasteful number, since it uses less digits than its factorization.

21374587 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1644212.

The product of its digits is 47040, while the sum is 37.

The square root of 21374587 is about 4623.2658370464. The cubic root of 21374587 is about 277.5231677219.

It can be divided in two parts, 2137 and 4587, that added together give a square (6724 = 82²).

The spelling of 21374587 in words is "twenty-one million, three hundred seventy-four thousand, five hundred eighty-seven".