21451056 has 40 divisors (see below), whose sum is σ = 60454464. Its totient is φ = 6500160.

The previous prime is 21451033. The next prime is 21451063. The reversal of 21451056 is 65015412.

21451056 = T₁₅₈ + T₁₅₉ + ... + T₅₀₉.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19786 + ... + 20841.

Almost surely, 2^21451056 is an apocalyptic number.

It is an amenable number.

21451056 is an abundant number, since it is smaller than the sum of its proper divisors (39003408).

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

21451056 is a wasteful number, since it uses less digits than its factorization.

21451056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40649 (or 40643 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 21451056 is about 4631.5284734092. The cubic root of 21451056 is about 277.8537263378.

Adding to 21451056 its reverse (65015412), we get a palindrome (86466468).

The spelling of 21451056 in words is "twenty-one million, four hundred fifty-one thousand, fifty-six".