21205530746 has 8 divisors (see below), whose sum is σ = 31820439924. Its totient is φ = 10598717440.

The previous prime is 21205530739. The next prime is 21205530757. The reversal of 21205530746 is 64703550212.

It can be written as a sum of positive squares in 2 ways, for example, as 21168795025 + 36735721 = 145495^2 + 6061^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2017415 + ... + 2027898.

Almost surely, 2^21205530746 is an apocalyptic number.

21205530746 is a deficient number, since it is larger than the sum of its proper divisors (10614909178).

21205530746 is a wasteful number, since it uses less digits than its factorization.

21205530746 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4047936.

The product of its (nonzero) digits is 50400, while the sum is 35.

The spelling of 21205530746 in words is "twenty-one billion, two hundred five million, five hundred thirty thousand, seven hundred forty-six".