821708677405 has 144 divisors (see below), whose sum is σ = 1321655771520. Its totient is φ = 487712628480.

The previous prime is 821708677381. The next prime is 821708677417. The reversal of 821708677405 is 504776807128.

It is not a de Polignac number, because 821708677405 - 2⁷ = 821708677277 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (55).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 154773891 + ... + 154779199.

It is an arithmetic number, because the mean of its divisors is an integer number (9178165080).

Almost surely, 2^821708677405 is an apocalyptic number.

It is an amenable number.

821708677405 is a deficient number, since it is larger than the sum of its proper divisors (499947094115).

821708677405 is a wasteful number, since it uses less digits than its factorization.

821708677405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5600 (or 5582 counting only the distinct ones).

The product of its (nonzero) digits is 5268480, while the sum is 55.

The spelling of 821708677405 in words is "eight hundred twenty-one billion, seven hundred eight million, six hundred seventy-seven thousand, four hundred five".