428481721 has 8 divisors (see below), whose sum is σ = 442669824. Its totient is φ = 414316560.

The previous prime is 428481661. The next prime is 428481737. The reversal of 428481721 is 127184824.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 428481721 - 2¹⁹ = 427957433 is a prime.

It is a super-2 number, since 2×428481721² = 367193170462243682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (428581721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37530 + ... + 47596.

It is an arithmetic number, because the mean of its divisors is an integer number (55333728).

Almost surely, 2^428481721 is an apocalyptic number.

It is an amenable number.

428481721 is a deficient number, since it is larger than the sum of its proper divisors (14188103).

428481721 is a wasteful number, since it uses less digits than its factorization.

428481721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11471.

The product of its digits is 28672, while the sum is 37.

The square root of 428481721 is about 20699.8000231886. The cubic root of 428481721 is about 753.8948326186.

The spelling of 428481721 in words is "four hundred twenty-eight million, four hundred eighty-one thousand, seven hundred twenty-one".