21421345 has 8 divisors (see below), whose sum is σ = 28042560. Its totient is φ = 15579120.

The previous prime is 21421333. The next prime is 21421373. The reversal of 21421345 is 54312412.

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

It is not a de Polignac number, because 21421345 - 2¹⁹ = 20897057 is a prime.

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, 194685 + ... + 194794.

It is an arithmetic number, because the mean of its divisors is an integer number (3505320).

Almost surely, 2^21421345 is an apocalyptic number.

It is an amenable number.

21421345 is a deficient number, since it is larger than the sum of its proper divisors (6621215).

21421345 is a wasteful number, since it uses less digits than its factorization.

21421345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 389495.

The product of its digits is 960, while the sum is 22.

The square root of 21421345 is about 4628.3198895496. The cubic root of 21421345 is about 277.7253857041.

Adding to 21421345 its reverse (54312412), we get a palindrome (75733757).

The spelling of 21421345 in words is "twenty-one million, four hundred twenty-one thousand, three hundred forty-five".