21401442 has 16 divisors (see below), whose sum is σ = 47558880. Its totient is φ = 7133796.

The previous prime is 21401441. The next prime is 21401447. The reversal of 21401442 is 24410412.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21401441) 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, 198108 + ... + 198215.

It is an arithmetic number, because the mean of its divisors is an integer number (2972430).

Almost surely, 2^21401442 is an apocalyptic number.

21401442 is an abundant number, since it is smaller than the sum of its proper divisors (26157438).

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

21401442 is a wasteful number, since it uses less digits than its factorization.

21401442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396334 (or 396328 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 21401442 is about 4626.1692576040. The cubic root of 21401442 is about 277.6393456482.

Adding to 21401442 its reverse (24410412), we get a palindrome (45811854).

The spelling of 21401442 in words is "twenty-one million, four hundred one thousand, four hundred forty-two".