21204647077 has 8 divisors (see below), whose sum is σ = 22548343896. Its totient is φ = 19871657472.

The previous prime is 21204647069. The next prime is 21204647081. The reversal of 21204647077 is 77074640212.

It can be written as a sum of positive squares in 4 ways, for example, as 8641375681 + 12563271396 = 92959^2 + 112086^2 .

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 21204647077 - 2³ = 21204647069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21204647047) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2672718 + ... + 2680639.

It is an arithmetic number, because the mean of its divisors is an integer number (2818542987).

Almost surely, 2^21204647077 is an apocalyptic number.

It is an amenable number.

21204647077 is a deficient number, since it is larger than the sum of its proper divisors (1343696819).

21204647077 is a wasteful number, since it uses less digits than its factorization.

21204647077 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5353607.

The product of its (nonzero) digits is 131712, while the sum is 40.

The spelling of 21204647077 in words is "twenty-one billion, two hundred four million, six hundred forty-seven thousand, seventy-seven".