21148444 has 12 divisors (see below), whose sum is σ = 38957800. Its totient is φ = 10017648.

The previous prime is 21148427. The next prime is 21148481. The reversal of 21148444 is 44484112.

It is a super-2 number, since 2×21148444² = 894513367242272, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 139059 + ... + 139210.

Almost surely, 2^21148444 is an apocalyptic number.

It is an amenable number.

21148444 is a deficient number, since it is larger than the sum of its proper divisors (17809356).

21148444 is a wasteful number, since it uses less digits than its factorization.

21148444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 278292 (or 278290 counting only the distinct ones).

The product of its digits is 4096, while the sum is 28.

The square root of 21148444 is about 4598.7437415016. The cubic root of 21148444 is about 276.5409644929.

The spelling of 21148444 in words is "twenty-one million, one hundred forty-eight thousand, four hundred forty-four".