821478564 has 24 divisors (see below), whose sum is σ = 2129759520. Its totient is φ = 273826152.

The previous prime is 821478527. The next prime is 821478601. The reversal of 821478564 is 465874128.

821478564 is a `hidden beast` number, since 8 + 2 + 14 + 78 + 564 = 666.

It is an interprime number because it is at equal distance from previous prime (821478527) and next prime (821478601).

It is a super-2 number, since 2×821478564² = 1349654062223004192, which contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

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, 3803034 + ... + 3803249.

It is an arithmetic number, because the mean of its divisors is an integer number (88739980).

Almost surely, 2^821478564 is an apocalyptic number.

It is an amenable number.

821478564 is an abundant number, since it is smaller than the sum of its proper divisors (1308280956).

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

821478564 is a wasteful number, since it uses less digits than its factorization.

821478564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7606296 (or 7606288 counting only the distinct ones).

The product of its digits is 430080, while the sum is 45.

The square root of 821478564 is about 28661.4473465664. The cubic root of 821478564 is about 936.5523941821.

The spelling of 821478564 in words is "eight hundred twenty-one million, four hundred seventy-eight thousand, five hundred sixty-four".