21407307661 has 8 divisors (see below), whose sum is σ = 22357978560. Its totient is φ = 20458296672.

The previous prime is 21407307659. The next prime is 21407307769. The reversal of 21407307661 is 16670370412.

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 21407307661 - 2¹ = 21407307659 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 21407307661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21407307611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 388576 + ... + 440233.

It is an arithmetic number, because the mean of its divisors is an integer number (2794747320).

Almost surely, 2^21407307661 is an apocalyptic number.

It is an amenable number.

21407307661 is a deficient number, since it is larger than the sum of its proper divisors (950670899).

21407307661 is a wasteful number, since it uses less digits than its factorization.

21407307661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 829955.

The product of its (nonzero) digits is 42336, while the sum is 37.

The spelling of 21407307661 in words is "twenty-one billion, four hundred seven million, three hundred seven thousand, six hundred sixty-one".