21246745 has 8 divisors (see below), whose sum is σ = 27457416. Its totient is φ = 15689856.

The previous prime is 21246721. The next prime is 21246751. The reversal of 21246745 is 54764212.

It can be written as a sum of positive squares in 4 ways, for example, as 1104601 + 20142144 = 1051^2 + 4488^2 .

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

It is not a de Polignac number, because 21246745 - 2⁵ = 21246713 is a prime.

It is a Duffinian number.

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, 163372 + ... + 163501.

It is an arithmetic number, because the mean of its divisors is an integer number (3432177).

Almost surely, 2^21246745 is an apocalyptic number.

It is an amenable number.

21246745 is a deficient number, since it is larger than the sum of its proper divisors (6210671).

21246745 is a wasteful number, since it uses less digits than its factorization.

21246745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 326891.

The product of its digits is 13440, while the sum is 31.

The square root of 21246745 is about 4609.4191608054. The cubic root of 21246745 is about 276.9687696939.

The spelling of 21246745 in words is "twenty-one million, two hundred forty-six thousand, seven hundred forty-five".