20964780521 has 4 divisors (see below), whose sum is σ = 20965691472. Its totient is φ = 20963869572.

The previous prime is 20964780491. The next prime is 20964780539. The reversal of 20964780521 is 12508746902.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20964780521 is a prime.

It is a super-3 number, since 3×20964780521³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20964780821) 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 3 ways as a sum of consecutive naturals, for example, 420035 + ... + 467288.

It is an arithmetic number, because the mean of its divisors is an integer number (5241422868).

Almost surely, 2^20964780521 is an apocalyptic number.

It is an amenable number.

20964780521 is a deficient number, since it is larger than the sum of its proper divisors (910951).

20964780521 is an equidigital number, since it uses as much as digits as its factorization.

20964780521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 910950.

The product of its (nonzero) digits is 241920, while the sum is 44.

The spelling of 20964780521 in words is "twenty billion, nine hundred sixty-four million, seven hundred eighty thousand, five hundred twenty-one".