649636551 has 16 divisors (see below), whose sum is σ = 978739200. Its totient is φ = 425749464.

The previous prime is 649636549. The next prime is 649636567. The reversal of 649636551 is 155636946.

649636551 is a `hidden beast` number, since 6 + 4 + 9 + 636 + 5 + 5 + 1 = 666.

It is not a de Polignac number, because 649636551 - 2¹ = 649636549 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 649636497 and 649636506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649636571) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 202311 + ... + 205496.

It is an arithmetic number, because the mean of its divisors is an integer number (61171200).

Almost surely, 2^649636551 is an apocalyptic number.

649636551 is a deficient number, since it is larger than the sum of its proper divisors (329102649).

649636551 is a wasteful number, since it uses less digits than its factorization.

649636551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407875 (or 407869 counting only the distinct ones).

The product of its digits is 583200, while the sum is 45.

The square root of 649636551 is about 25487.9687499808. The cubic root of 649636551 is about 866.0776220410.

The spelling of 649636551 in words is "six hundred forty-nine million, six hundred thirty-six thousand, five hundred fifty-one".