820973626621 has 4 divisors (see below), whose sum is σ = 820975904892. Its totient is φ = 820971348352.

The previous prime is 820973626609. The next prime is 820973626639. The reversal of 820973626621 is 126626379028.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 452754036900 + 368219589721 = 672870^2 + 606811^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-820973626621 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 (820973626601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 466036 + ... + 1363501.

It is an arithmetic number, because the mean of its divisors is an integer number (205243976223).

Almost surely, 2^820973626621 is an apocalyptic number.

It is an amenable number.

820973626621 is a deficient number, since it is larger than the sum of its proper divisors (2278271).

820973626621 is a wasteful number, since it uses less digits than its factorization.

820973626621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2278270.

The product of its (nonzero) digits is 2612736, while the sum is 52.

The spelling of 820973626621 in words is "eight hundred twenty billion, nine hundred seventy-three million, six hundred twenty-six thousand, six hundred twenty-one".