21683406 has 16 divisors (see below), whose sum is σ = 44539344. Its totient is φ = 7032384.

The previous prime is 21683393. The next prime is 21683419. The reversal of 21683406 is 60438612.

It is an interprime number because it is at equal distance from previous prime (21683393) and next prime (21683419).

It is a congruent number.

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, 48615 + ... + 49058.

It is an arithmetic number, because the mean of its divisors is an integer number (2783709).

Almost surely, 2^21683406 is an apocalyptic number.

21683406 is an abundant number, since it is smaller than the sum of its proper divisors (22855938).

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

21683406 is a wasteful number, since it uses less digits than its factorization.

21683406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97715.

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 21683406 is about 4656.5444269329. The cubic root of 21683406 is about 278.8533292110.

The spelling of 21683406 in words is "twenty-one million, six hundred eighty-three thousand, four hundred six".