21586745 has 8 divisors (see below), whose sum is σ = 25941384. Its totient is φ = 17244544.

The previous prime is 21586739. The next prime is 21586837. The reversal of 21586745 is 54768512.

It can be written as a sum of positive squares in 4 ways, for example, as 94249 + 21492496 = 307^2 + 4636^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21586745 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21586699 and 21586708.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1277 + ... + 6693.

It is an arithmetic number, because the mean of its divisors is an integer number (3242673).

Almost surely, 2^21586745 is an apocalyptic number.

It is an amenable number.

21586745 is a deficient number, since it is larger than the sum of its proper divisors (4354639).

21586745 is an equidigital number, since it uses as much as digits as its factorization.

21586745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6219.

The product of its digits is 67200, while the sum is 38.

The square root of 21586745 is about 4646.1537856597. The cubic root of 21586745 is about 278.4383514527.

It can be divided in two parts, 2158 and 6745, that multiplied together give a triangular number (14555710 = T₅₃₉₅).

The spelling of 21586745 in words is "twenty-one million, five hundred eighty-six thousand, seven hundred forty-five".