21532040643 has 32 divisors (see below), whose sum is σ = 30987452160. Its totient is φ = 13254658560.

The previous prime is 21532040639. The next prime is 21532040687. The reversal of 21532040643 is 34604023512.

It is a Cunningham number, because it is equal to 146738²-1.

It is not a de Polignac number, because 21532040643 - 2² = 21532040639 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21532040643.

It is not an unprimeable number, because it can be changed into a prime (21532040143) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 2784180 + ... + 2791902.

It is an arithmetic number, because the mean of its divisors is an integer number (968357880).

Almost surely, 2^21532040643 is an apocalyptic number.

21532040643 is a deficient number, since it is larger than the sum of its proper divisors (9455411517).

21532040643 is a wasteful number, since it uses less digits than its factorization.

21532040643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8979.

The product of its (nonzero) digits is 17280, while the sum is 30.

The spelling of 21532040643 in words is "twenty-one billion, five hundred thirty-two million, forty thousand, six hundred forty-three".