21451944 has 32 divisors (see below), whose sum is σ = 53766720. Its totient is φ = 7132416.

The previous prime is 21451933. The next prime is 21451949. The reversal of 21451944 is 44915412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21451949) 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 7 ways as a sum of consecutive naturals, for example, 11184 + ... + 12960.

It is an arithmetic number, because the mean of its divisors is an integer number (1680210).

Almost surely, 2^21451944 is an apocalyptic number.

21451944 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21451944 is an abundant number, since it is smaller than the sum of its proper divisors (32314776).

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

21451944 is a wasteful number, since it uses less digits than its factorization.

21451944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2289 (or 2285 counting only the distinct ones).

The product of its digits is 5760, while the sum is 30.

The square root of 21451944 is about 4631.6243370982. The cubic root of 21451944 is about 277.8575603481.

The spelling of 21451944 in words is "twenty-one million, four hundred fifty-one thousand, nine hundred forty-four".