649689121 has 9 divisors (see below), whose sum is σ = 660809233. Its totient is φ = 638754340.

The previous prime is 649689091. The next prime is 649689133. The reversal of 649689121 is 121986946.

It is a happy number.

The square root of 649689121 is 25489.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 649689121 - 2¹⁹ = 649164833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (649689191) 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, 1809540 + ... + 1809898.

Almost surely, 2^649689121 is an apocalyptic number.

649689121 is the 25489-th square number.

649689121 is the 12745-th centered octagonal number.

It is an amenable number.

649689121 is a deficient number, since it is larger than the sum of its proper divisors (11120112).

649689121 is an frugal number, since it uses more digits than its factorization.

649689121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 860 (or 430 counting only the distinct ones).

The product of its digits is 186624, while the sum is 46.

The cubic root of 649689121 is about 866.1009830380.

Multiplying 649689121 by its product of digits (186624), we get a square (121247582517504 = 11011248²).

The spelling of 649689121 in words is "six hundred forty-nine million, six hundred eighty-nine thousand, one hundred twenty-one".