21155416 has 16 divisors (see below), whose sum is σ = 40739040. Its totient is φ = 10291680.

The previous prime is 21155411. The next prime is 21155419. The reversal of 21155416 is 61455112.

It is a happy number.

It is a super-2 number, since 2×21155416² = 895103252266112, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155411) 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 3 ways as a sum of consecutive naturals, for example, 35440 + ... + 36031.

It is an arithmetic number, because the mean of its divisors is an integer number (2546190).

Almost surely, 2^21155416 is an apocalyptic number.

It is an amenable number.

21155416 is a deficient number, since it is larger than the sum of its proper divisors (19583624).

21155416 is a wasteful number, since it uses less digits than its factorization.

21155416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71514 (or 71510 counting only the distinct ones).

The product of its digits is 1200, while the sum is 25.

The square root of 21155416 is about 4599.5017121423. The cubic root of 21155416 is about 276.5713502078.

The spelling of 21155416 in words is "twenty-one million, one hundred fifty-five thousand, four hundred sixteen".