21452401566 has 24 divisors (see below), whose sum is σ = 47173940424. Its totient is φ = 7044071760.

The previous prime is 21452401519. The next prime is 21452401577. The reversal of 21452401566 is 66510425412.

21452401566 is a `hidden beast` number, since 2 + 1 + 4 + 52 + 40 + 1 + 566 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 21452401566.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8892825 + ... + 8895236.

It is an arithmetic number, because the mean of its divisors is an integer number (1965580851).

Almost surely, 2^21452401566 is an apocalyptic number.

21452401566 is an abundant number, since it is smaller than the sum of its proper divisors (25721538858).

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

21452401566 is a wasteful number, since it uses less digits than its factorization.

21452401566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17788136 (or 17788133 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

Adding to 21452401566 its reverse (66510425412), we get a palindrome (87962826978).

The spelling of 21452401566 in words is "twenty-one billion, four hundred fifty-two million, four hundred one thousand, five hundred sixty-six".