447787921 has 9 divisors (see below), whose sum is σ = 521068521.
Its totient is φ = 383691252.
The previous prime is 447787909. The next prime is 447787961. The reversal of 447787921 is 129787744.
It is a happy number.
The square root of 447787921 is 21161.
It is a perfect power (a square), and thus also a powerful number.
It is not a de Polignac number, because 447787921 - 25 = 447787889 is a prime.
It is a Harshad number since it is a multiple of its sum of digits (49).
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (447787961) by changing a digit.
It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 146616 + ... + 149638.
Almost surely, 2447787921 is an apocalyptic number.
447787921 is the 21161-st square number.
447787921 is the 10581-st centered octagonal number.
It is an amenable number.
447787921 is a deficient number, since it is larger than the sum of its proper divisors (73280600).
447787921 is an frugal number, since it uses more digits than its factorization.
447787921 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 6060 (or 3030 counting only the distinct ones).
The product of its digits is 790272, while the sum is 49.
The cubic root of 447787921 is about 765.0517122262.
Multiplying 447787921 by its sum of digits (49), we get a square (21941608129 = 1481272).
447787921 divided by its sum of digits (49) gives a square (9138529 = 30232).
The spelling of 447787921 in words is "four hundred forty-seven million, seven hundred eighty-seven thousand, nine hundred twenty-one".