21466564645 has 16 divisors (see below), whose sum is σ = 25828552512. Its totient is φ = 17127532800.

The previous prime is 21466564633. The next prime is 21466564657. The reversal of 21466564645 is 54646566412.

It is an interprime number because it is at equal distance from previous prime (21466564633) and next prime (21466564657).

It is not a de Polignac number, because 21466564645 - 2¹⁹ = 21466040357 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3375789 + ... + 3382141.

It is an arithmetic number, because the mean of its divisors is an integer number (1614284532).

Almost surely, 2^21466564645 is an apocalyptic number.

It is an amenable number.

21466564645 is a deficient number, since it is larger than the sum of its proper divisors (4361987867).

21466564645 is a wasteful number, since it uses less digits than its factorization.

21466564645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8052.

The product of its digits is 4147200, while the sum is 49.

The spelling of 21466564645 in words is "twenty-one billion, four hundred sixty-six million, five hundred sixty-four thousand, six hundred forty-five".