21001694 has 36 divisors (see below), whose sum is σ = 38035872. Its totient is φ = 8671320.

The previous prime is 21001693. The next prime is 21001703. The reversal of 21001694 is 49610012.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001693) 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 17 ways as a sum of consecutive naturals, for example, 94067 + ... + 94289.

It is an arithmetic number, because the mean of its divisors is an integer number (1056552).

Almost surely, 2^21001694 is an apocalyptic number.

21001694 is a deficient number, since it is larger than the sum of its proper divisors (17034178).

21001694 is a wasteful number, since it uses less digits than its factorization.

21001694 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 301 (or 263 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 21001694 is about 4582.7605217816. The cubic root of 21001694 is about 275.8998358792.

The spelling of 21001694 in words is "twenty-one million, one thousand, six hundred ninety-four".