649061991 has 12 divisors (see below), whose sum is σ = 972257832. Its totient is φ = 432707832.

The previous prime is 649061977. The next prime is 649062013. The reversal of 649061991 is 199160946.

It is not a de Polignac number, because 649061991 - 2⁶ = 649061927 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649061951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1335276 + ... + 1335761.

It is an arithmetic number, because the mean of its divisors is an integer number (81021486).

Almost surely, 2^649061991 is an apocalyptic number.

649061991 is a deficient number, since it is larger than the sum of its proper divisors (323195841).

649061991 is an equidigital number, since it uses as much as digits as its factorization.

649061991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2671052 (or 2671040 counting only the distinct ones).

The product of its (nonzero) digits is 104976, while the sum is 45.

The square root of 649061991 is about 25476.6950564629. The cubic root of 649061991 is about 865.8222175219.

The spelling of 649061991 in words is "six hundred forty-nine million, sixty-one thousand, nine hundred ninety-one".