21396042 has 32 divisors (see below), whose sum is σ = 48029760. Its totient is φ = 7059600.

The previous prime is 21396031. The next prime is 21396043. The reversal of 21396042 is 24069312.

21396042 is a `hidden beast` number, since 21 + 39 + 604 + 2 = 666.

It is a super-2 number, since 2×21396042² = 915581226531528, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 21395997 and 21396015.

It is not an unprimeable number, because it can be changed into a prime (21396043) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3493 + ... + 7415.

It is an arithmetic number, because the mean of its divisors is an integer number (1500930).

Almost surely, 2^21396042 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21396042, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24014880).

21396042 is an abundant number, since it is smaller than the sum of its proper divisors (26633718).

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

21396042 is a wasteful number, since it uses less digits than its factorization.

21396042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4035 (or 4029 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 21396042 is about 4625.5855845503. The cubic root of 21396042 is about 277.6159924153.

The spelling of 21396042 in words is "twenty-one million, three hundred ninety-six thousand, forty-two".