1997720650 has 24 divisors (see below), whose sum is σ = 3816189900. Its totient is φ = 777490560.

The previous prime is 1997720639. The next prime is 1997720653. The reversal of 1997720650 is 560277991.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 1074593961 + 923126689 = 32781^2 + 30383^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1997720650.

It is not an unprimeable number, because it can be changed into a prime (1997720653) 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, 538075 + ... + 541774.

Almost surely, 2^1997720650 is an apocalyptic number.

1997720650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1997720650 is a deficient number, since it is larger than the sum of its proper divisors (1818469250).

1997720650 is a wasteful number, since it uses less digits than its factorization.

1997720650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1079898 (or 1079893 counting only the distinct ones).

The product of its (nonzero) digits is 238140, while the sum is 46.

The square root of 1997720650 is about 44695.8683772896. The cubic root of 1997720650 is about 1259.4422344433.

The spelling of 1997720650 in words is "one billion, nine hundred ninety-seven million, seven hundred twenty thousand, six hundred fifty".