820642493 has 16 divisors (see below), whose sum is σ = 929188800. Its totient is φ = 717924480.

The previous prime is 820642489. The next prime is 820642523. The reversal of 820642493 is 394246028.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 820642493 - 2² = 820642489 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 (820642423) 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, 95738 + ... + 103956.

It is an arithmetic number, because the mean of its divisors is an integer number (58074300).

Almost surely, 2^820642493 is an apocalyptic number.

It is an amenable number.

820642493 is a deficient number, since it is larger than the sum of its proper divisors (108546307).

820642493 is a wasteful number, since it uses less digits than its factorization.

820642493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8572.

The product of its (nonzero) digits is 82944, while the sum is 38.

The square root of 820642493 is about 28646.8583443281. The cubic root of 820642493 is about 936.2345566771.

The spelling of 820642493 in words is "eight hundred twenty million, six hundred forty-two thousand, four hundred ninety-three".