649742689 has 4 divisors (see below), whose sum is σ = 657967360. Its totient is φ = 641518020.

The previous prime is 649742683. The next prime is 649742693. The reversal of 649742689 is 986247946.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 986247946 = 2 ⋅493123973.

It is a cyclic number.

It is not a de Polignac number, because 649742689 - 2¹³ = 649734497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (649742683) 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, 4112217 + ... + 4112374.

It is an arithmetic number, because the mean of its divisors is an integer number (164491840).

Almost surely, 2^649742689 is an apocalyptic number.

It is an amenable number.

649742689 is a deficient number, since it is larger than the sum of its proper divisors (8224671).

649742689 is an equidigital number, since it uses as much as digits as its factorization.

649742689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8224670.

The product of its digits is 5225472, while the sum is 55.

The square root of 649742689 is about 25490.0507845708. The cubic root of 649742689 is about 866.1247862288.

The spelling of 649742689 in words is "six hundred forty-nine million, seven hundred forty-two thousand, six hundred eighty-nine".