649951 has 4 divisors (see below), whose sum is σ = 652032. Its totient is φ = 647872.

The previous prime is 649937. The next prime is 649969. The reversal of 649951 is 159946.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 159946 = 2 ⋅79973.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-649951 is a prime.

It is a Duffinian number.

649951 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649921) 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, 466 + ... + 1231.

It is an arithmetic number, because the mean of its divisors is an integer number (163008).

2⁶⁴⁹⁹⁵¹ is an apocalyptic number.

649951 is a deficient number, since it is larger than the sum of its proper divisors (2081).

649951 is a wasteful number, since it uses less digits than its factorization.

649951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2080.

The product of its digits is 9720, while the sum is 34.

The square root of 649951 is about 806.1953857472. The cubic root of 649951 is about 86.6217337760.

It can be divided in two parts, 649 and 951, that added together give a square (1600 = 40²).

The spelling of 649951 in words is "six hundred forty-nine thousand, nine hundred fifty-one".