649640237 has 4 divisors (see below), whose sum is σ = 650144736. Its totient is φ = 649135740.

The previous prime is 649640207. The next prime is 649640287. The reversal of 649640237 is 732046946.

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: 732046946 = 2 ⋅366023473.

It is a cyclic number.

It is not a de Polignac number, because 649640237 - 2¹⁴ = 649623853 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 649640194 and 649640203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649640207) 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, 250313 + ... + 252894.

It is an arithmetic number, because the mean of its divisors is an integer number (162536184).

Almost surely, 2^649640237 is an apocalyptic number.

It is an amenable number.

649640237 is a deficient number, since it is larger than the sum of its proper divisors (504499).

649640237 is a wasteful number, since it uses less digits than its factorization.

649640237 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 504498.

The product of its (nonzero) digits is 217728, while the sum is 41.

The square root of 649640237 is about 25488.0410585043. The cubic root of 649640237 is about 866.0792600626.

The spelling of 649640237 in words is "six hundred forty-nine million, six hundred forty thousand, two hundred thirty-seven".