21340407 has 12 divisors (see below), whose sum is σ = 31276280. Its totient is φ = 12933360.

The previous prime is 21340387. The next prime is 21340409. The reversal of 21340407 is 70404312.

It is not a de Polignac number, because 21340407 - 2⁷ = 21340279 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21340409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 29032 + ... + 29757.

Almost surely, 2^21340407 is an apocalyptic number.

21340407 is a deficient number, since it is larger than the sum of its proper divisors (9935873).

21340407 is a wasteful number, since it uses less digits than its factorization.

21340407 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58814 (or 58803 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 21.

The square root of 21340407 is about 4619.5678369302. The cubic root of 21340407 is about 277.3751601437.

Adding to 21340407 its reverse (70404312), we get a palindrome (91744719).

The spelling of 21340407 in words is "twenty-one million, three hundred forty thousand, four hundred seven".