21401842 has 32 divisors (see below), whose sum is σ = 41324544. Its totient is φ = 8067600.

The previous prime is 21401839. The next prime is 21401843. The reversal of 21401842 is 24810412.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is not an unprimeable number, because it can be changed into a prime (21401843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2533 + ... + 7015.

It is an arithmetic number, because the mean of its divisors is an integer number (1291392).

Almost surely, 2^21401842 is an apocalyptic number.

21401842 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21401842 is a deficient number, since it is larger than the sum of its proper divisors (19922702).

21401842 is a wasteful number, since it uses less digits than its factorization.

21401842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4534.

The product of its (nonzero) digits is 512, while the sum is 22.

The square root of 21401842 is about 4626.2124897155. The cubic root of 21401842 is about 277.6410753610.

The spelling of 21401842 in words is "twenty-one million, four hundred one thousand, eight hundred forty-two".