21345670 has 32 divisors (see below), whose sum is σ = 40755456. Its totient is φ = 8035200.

The previous prime is 21345637. The next prime is 21345703. The reversal of 21345670 is 7654312.

It is an interprime number because it is at equal distance from previous prime (21345637) and next prime (21345703).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10540 + ... + 12400.

It is an arithmetic number, because the mean of its divisors is an integer number (1273608).

Almost surely, 2^21345670 is an apocalyptic number.

21345670 is a deficient number, since it is larger than the sum of its proper divisors (19409786).

21345670 is a wasteful number, since it uses less digits than its factorization.

21345670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1936.

The product of its (nonzero) digits is 5040, while the sum is 28.

The square root of 21345670 is about 4620.1374438430. The cubic root of 21345670 is about 277.3979604816.

Adding to 21345670 its reverse (7654312), we get a palindrome (28999982).

The spelling of 21345670 in words is "twenty-one million, three hundred forty-five thousand, six hundred seventy".