21455416 has 8 divisors (see below), whose sum is σ = 40228920. Its totient is φ = 10727704.

The previous prime is 21455393. The next prime is 21455429. The reversal of 21455416 is 61455412.

It is a tau number, because it is divible by the number of its divisors (8).

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 as a sum of consecutive naturals, namely, 1340956 + ... + 1340971.

It is an arithmetic number, because the mean of its divisors is an integer number (5028615).

Almost surely, 2^21455416 is an apocalyptic number.

It is an amenable number.

21455416 is a deficient number, since it is larger than the sum of its proper divisors (18773504).

21455416 is a wasteful number, since it uses less digits than its factorization.

21455416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2681933 (or 2681929 counting only the distinct ones).

The product of its digits is 4800, while the sum is 28.

The square root of 21455416 is about 4631.9991364421. Note that the first 3 decimals coincide. The cubic root of 21455416 is about 277.8725499671.

The spelling of 21455416 in words is "twenty-one million, four hundred fifty-five thousand, four hundred sixteen".