20821617307 has 16 divisors (see below), whose sum is σ = 21844753920. Its totient is φ = 19808597952.

The previous prime is 20821617247. The next prime is 20821617317. The reversal of 20821617307 is 70371612802.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20821617307 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20821617317) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3502944 + ... + 3508882.

It is an arithmetic number, because the mean of its divisors is an integer number (1365297120).

Almost surely, 2^20821617307 is an apocalyptic number.

20821617307 is a deficient number, since it is larger than the sum of its proper divisors (1023136613).

20821617307 is a wasteful number, since it uses less digits than its factorization.

20821617307 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6762.

The product of its (nonzero) digits is 28224, while the sum is 37.

The spelling of 20821617307 in words is "twenty billion, eight hundred twenty-one million, six hundred seventeen thousand, three hundred seven".