21690646563 has 32 divisors (see below), whose sum is σ = 31375590400. Its totient is φ = 13284292896.

The previous prime is 21690646559. The next prime is 21690646589. The reversal of 21690646563 is 36564609612.

It is a happy number.

It is not a de Polignac number, because 21690646563 - 2² = 21690646559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21690646063) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 308856 + ... + 372522.

It is an arithmetic number, because the mean of its divisors is an integer number (980487200).

Almost surely, 2^21690646563 is an apocalyptic number.

21690646563 is a deficient number, since it is larger than the sum of its proper divisors (9684943837).

21690646563 is a wasteful number, since it uses less digits than its factorization.

21690646563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63871.

The product of its (nonzero) digits is 1399680, while the sum is 48.

The spelling of 21690646563 in words is "twenty-one billion, six hundred ninety million, six hundred forty-six thousand, five hundred sixty-three".