906432721 has 4 divisors (see below), whose sum is σ = 907046244. Its totient is φ = 905819200.

The previous prime is 906432719. The next prime is 906432727. The reversal of 906432721 is 127234609.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 175271121 + 731161600 = 13239^2 + 27040^2 .

It is a cyclic number.

It is not a de Polignac number, because 906432721 - 2¹ = 906432719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (906432727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 304540 + ... + 307501.

It is an arithmetic number, because the mean of its divisors is an integer number (226761561).

Almost surely, 2^906432721 is an apocalyptic number.

It is an amenable number.

906432721 is a deficient number, since it is larger than the sum of its proper divisors (613523).

906432721 is a wasteful number, since it uses less digits than its factorization.

906432721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 613522.

The product of its (nonzero) digits is 18144, while the sum is 34.

The square root of 906432721 is about 30107.0211246480. The cubic root of 906432721 is about 967.7841939887.

The spelling of 906432721 in words is "nine hundred six million, four hundred thirty-two thousand, seven hundred twenty-one".