21389894 has 8 divisors (see below), whose sum is σ = 32611008. Its totient is φ = 10519560.

The previous prime is 21389891. The next prime is 21389903. The reversal of 21389894 is 49898312.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21389891) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87542 + ... + 87785.

It is an arithmetic number, because the mean of its divisors is an integer number (4076376).

Almost surely, 2^21389894 is an apocalyptic number.

21389894 is a deficient number, since it is larger than the sum of its proper divisors (11221114).

21389894 is a wasteful number, since it uses less digits than its factorization.

21389894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 175390.

The product of its digits is 124416, while the sum is 44.

The square root of 21389894 is about 4624.9209722978. The cubic root of 21389894 is about 277.5893995432.

The spelling of 21389894 in words is "twenty-one million, three hundred eighty-nine thousand, eight hundred ninety-four".