21400636 has 6 divisors (see below), whose sum is σ = 37451120. Its totient is φ = 10700316.

The previous prime is 21400597. The next prime is 21400667. The reversal of 21400636 is 63600412.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2675076 + ... + 2675083.

Almost surely, 2^21400636 is an apocalyptic number.

It is an amenable number.

21400636 is a deficient number, since it is larger than the sum of its proper divisors (16050484).

21400636 is a wasteful number, since it uses less digits than its factorization.

21400636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5350163 (or 5350161 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 21400636 is about 4626.0821436719. The cubic root of 21400636 is about 277.6358602114.

The spelling of 21400636 in words is "twenty-one million, four hundred thousand, six hundred thirty-six".