21893538 has 8 divisors (see below), whose sum is σ = 43787088. Its totient is φ = 7297844.

The previous prime is 21893537. The next prime is 21893551. The reversal of 21893538 is 83539812.

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

21893538 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 21893496 and 21893505.

It is not an unprimeable number, because it can be changed into a prime (21893537) 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, 1824456 + ... + 1824467.

It is an arithmetic number, because the mean of its divisors is an integer number (5473386).

Almost surely, 2^21893538 is an apocalyptic number.

21893538 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21893538 is a wasteful number, since it uses less digits than its factorization.

21893538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3648928.

The product of its digits is 51840, while the sum is 39.

The square root of 21893538 is about 4679.0531093374. The cubic root of 21893538 is about 279.7512160923.

The spelling of 21893538 in words is "twenty-one million, eight hundred ninety-three thousand, five hundred thirty-eight".