21388774 has 16 divisors (see below), whose sum is σ = 35343360. Its totient is φ = 9626760.

The previous prime is 21388769. The next prime is 21388777. The reversal of 21388774 is 47788312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21388777) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2454 + ... + 6985.

It is an arithmetic number, because the mean of its divisors is an integer number (2208960).

Almost surely, 2^21388774 is an apocalyptic number.

21388774 is a deficient number, since it is larger than the sum of its proper divisors (13954586).

21388774 is a wasteful number, since it uses less digits than its factorization.

21388774 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9555.

The product of its digits is 75264, while the sum is 40.

The square root of 21388774 is about 4624.7998875627. The cubic root of 21388774 is about 277.5845544895.

The spelling of 21388774 in words is "twenty-one million, three hundred eighty-eight thousand, seven hundred seventy-four".