21147894 has 12 divisors (see below), whose sum is σ = 45820476. Its totient is φ = 7049292.

The previous prime is 21147869. The next prime is 21147937. The reversal of 21147894 is 49874112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 587424 + ... + 587459.

It is an arithmetic number, because the mean of its divisors is an integer number (3818373).

Almost surely, 2^21147894 is an apocalyptic number.

21147894 is an abundant number, since it is smaller than the sum of its proper divisors (24672582).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21147894 is a wasteful number, since it uses less digits than its factorization.

21147894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1174891 (or 1174888 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 21147894 is about 4598.6839421730. The cubic root of 21147894 is about 276.5385671715.

The spelling of 21147894 in words is "twenty-one million, one hundred forty-seven thousand, eight hundred ninety-four".