21310303661 has 8 divisors (see below), whose sum is σ = 21925572120. Its totient is φ = 20697104448.

The previous prime is 21310303627. The next prime is 21310303667. The reversal of 21310303661 is 16630301312.

It can be written as a sum of positive squares in 4 ways, for example, as 6354481225 + 14955822436 = 79715^2 + 122294^2 .

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 21310303661 - 2¹⁸ = 21310041517 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21310303661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21310303667) 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, 496406 + ... + 537623.

It is an arithmetic number, because the mean of its divisors is an integer number (2740696515).

Almost surely, 2^21310303661 is an apocalyptic number.

It is an amenable number.

21310303661 is a deficient number, since it is larger than the sum of its proper divisors (615268459).

21310303661 is a wasteful number, since it uses less digits than its factorization.

21310303661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1034623.

The product of its (nonzero) digits is 1944, while the sum is 26.

Adding to 21310303661 its reverse (16630301312), we get a palindrome (37940604973).

The spelling of 21310303661 in words is "twenty-one billion, three hundred ten million, three hundred three thousand, six hundred sixty-one".