654855721 has 4 divisors (see below), whose sum is σ = 705229252. Its totient is φ = 604482192.

The previous prime is 654855709. The next prime is 654855739. The reversal of 654855721 is 127558456.

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 283754025 + 371101696 = 16845^2 + 19264^2 .

It is a cyclic number.

It is not a de Polignac number, because 654855721 - 2¹⁵ = 654822953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (654852721) 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, 25186746 + ... + 25186771.

It is an arithmetic number, because the mean of its divisors is an integer number (176307313).

Almost surely, 2^654855721 is an apocalyptic number.

It is an amenable number.

654855721 is a deficient number, since it is larger than the sum of its proper divisors (50373531).

654855721 is a wasteful number, since it uses less digits than its factorization.

654855721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50373530.

The product of its digits is 336000, while the sum is 43.

The square root of 654855721 is about 25590.1489053894. The cubic root of 654855721 is about 868.3907898103.

The spelling of 654855721 in words is "six hundred fifty-four million, eight hundred fifty-five thousand, seven hundred twenty-one".