1991648650 has 24 divisors (see below), whose sum is σ = 3709521504. Its totient is φ = 795572400.

The previous prime is 1991648531. The next prime is 1991648653. The reversal of 1991648650 is 568461991.

It is a junction number, because it is equal to n+sod(n) for n = 1991648594 and 1991648603.

It is not an unprimeable number, because it can be changed into a prime (1991648653) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10345 + ... + 63955.

It is an arithmetic number, because the mean of its divisors is an integer number (154563396).

Almost surely, 2^1991648650 is an apocalyptic number.

1991648650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1991648650 is a deficient number, since it is larger than the sum of its proper divisors (1717872854).

1991648650 is a wasteful number, since it uses less digits than its factorization.

1991648650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54366 (or 54361 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 49.

The square root of 1991648650 is about 44627.8909427725. The cubic root of 1991648650 is about 1258.1649296829.

The spelling of 1991648650 in words is "one billion, nine hundred ninety-one million, six hundred forty-eight thousand, six hundred fifty".