21039969961 has 8 divisors (see below), whose sum is σ = 21557301920. Its totient is φ = 20523912192.

The previous prime is 21039969949. The next prime is 21039969997. The reversal of 21039969961 is 16996993012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21039969961 - 2⁹ = 21039969449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21039969061) 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 7 ways as a sum of consecutive naturals, for example, 285075 + ... + 351208.

It is an arithmetic number, because the mean of its divisors is an integer number (2694662740).

Almost surely, 2^21039969961 is an apocalyptic number.

It is an amenable number.

21039969961 is a deficient number, since it is larger than the sum of its proper divisors (517331959).

21039969961 is an equidigital number, since it uses as much as digits as its factorization.

21039969961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 637095.

The product of its (nonzero) digits is 1417176, while the sum is 55.

The spelling of 21039969961 in words is "twenty-one billion, thirty-nine million, nine hundred sixty-nine thousand, nine hundred sixty-one".