21046394 has 4 divisors (see below), whose sum is σ = 31569594. Its totient is φ = 10523196.

The previous prime is 21046387. The next prime is 21046409. The reversal of 21046394 is 49364012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 17098225 + 3948169 = 4135^2 + 1987^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5261597 + ... + 5261600.

Almost surely, 2^21046394 is an apocalyptic number.

21046394 is a deficient number, since it is larger than the sum of its proper divisors (10523200).

21046394 is a wasteful number, since it uses less digits than its factorization.

21046394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10523199.

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 21046394 is about 4587.6349026486. The cubic root of 21046394 is about 276.0954388838.

The spelling of 21046394 in words is "twenty-one million, forty-six thousand, three hundred ninety-four".