820720464 has 20 divisors (see below), whose sum is σ = 2120194656. Its totient is φ = 273573472.

The previous prime is 820720379. The next prime is 820720471. The reversal of 820720464 is 464027028.

It is a congruent number.

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, 8549124 + ... + 8549219.

Almost surely, 2^820720464 is an apocalyptic number.

It is an amenable number.

820720464 is an abundant number, since it is smaller than the sum of its proper divisors (1299474192).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

820720464 is a wasteful number, since it uses less digits than its factorization.

820720464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17098354 (or 17098348 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 33.

The square root of 820720464 is about 28648.2192116718. The cubic root of 820720464 is about 936.2642069546.

The spelling of 820720464 in words is "eight hundred twenty million, seven hundred twenty thousand, four hundred sixty-four".