648991982 has 4 divisors (see below), whose sum is σ = 973487976. Its totient is φ = 324495990.

The previous prime is 648991969. The next prime is 648992009. The reversal of 648991982 is 289199846.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 162247994 + ... + 162247997.

It is an arithmetic number, because the mean of its divisors is an integer number (243371994).

Almost surely, 2^648991982 is an apocalyptic number.

648991982 is a deficient number, since it is larger than the sum of its proper divisors (324495994).

648991982 is a wasteful number, since it uses less digits than its factorization.

648991982 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 324495993.

The product of its digits is 2239488, while the sum is 56.

The square root of 648991982 is about 25475.3210382126. The cubic root of 648991982 is about 865.7910866860.

The spelling of 648991982 in words is "six hundred forty-eight million, nine hundred ninety-one thousand, nine hundred eighty-two".