649361681 has 8 divisors (see below), whose sum is σ = 670844928. Its totient is φ = 627912000.

The previous prime is 649361663. The next prime is 649361693. The reversal of 649361681 is 186163946.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-649361681 is a prime.

It is a super-2 number, since 2×649361681² = 843341185502291522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (649361621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34496 + ... + 49886.

It is an arithmetic number, because the mean of its divisors is an integer number (83855616).

Almost surely, 2^649361681 is an apocalyptic number.

It is an amenable number.

649361681 is a deficient number, since it is larger than the sum of its proper divisors (21483247).

649361681 is a wasteful number, since it uses less digits than its factorization.

649361681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16783.

The product of its digits is 186624, while the sum is 44.

The square root of 649361681 is about 25482.5760275526. The cubic root of 649361681 is about 865.9554550956.

The spelling of 649361681 in words is "six hundred forty-nine million, three hundred sixty-one thousand, six hundred eighty-one".