21354646 has 4 divisors (see below), whose sum is σ = 32031972. Its totient is φ = 10677322.

The previous prime is 21354589. The next prime is 21354653. The reversal of 21354646 is 64645312.

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

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5338660 + ... + 5338663.

It is an arithmetic number, because the mean of its divisors is an integer number (8007993).

Almost surely, 2^21354646 is an apocalyptic number.

21354646 is a deficient number, since it is larger than the sum of its proper divisors (10677326).

21354646 is a wasteful number, since it uses less digits than its factorization.

21354646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10677325.

The product of its digits is 17280, while the sum is 31.

The square root of 21354646 is about 4621.1087414169. The cubic root of 21354646 is about 277.4368376117.

Adding to 21354646 its reverse (64645312), we get a palindrome (85999958).

The spelling of 21354646 in words is "twenty-one million, three hundred fifty-four thousand, six hundred forty-six".