21148394 has 4 divisors (see below), whose sum is σ = 31722594. Its totient is φ = 10574196.

The previous prime is 21148381. The next prime is 21148411. The reversal of 21148394 is 49384112.

It is a happy number.

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., 20566225 + 582169 = 4535^2 + 763^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21148394.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5287097 + ... + 5287100.

Almost surely, 2^21148394 is an apocalyptic number.

21148394 is a deficient number, since it is larger than the sum of its proper divisors (10574200).

21148394 is a wasteful number, since it uses less digits than its factorization.

21148394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10574199.

The product of its digits is 6912, while the sum is 32.

The square root of 21148394 is about 4598.7383052311. The cubic root of 21148394 is about 276.5407465563.

The spelling of 21148394 in words is "twenty-one million, one hundred forty-eight thousand, three hundred ninety-four".