1997981601 has 32 divisors (see below), whose sum is σ = 3325516800. Its totient is φ = 1036601280.

The previous prime is 1997981591. The next prime is 1997981621. The reversal of 1997981601 is 1061897991.

It is not a de Polignac number, because 1997981601 - 2⁵ = 1997981569 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1997981621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 193395 + ... + 203463.

It is an arithmetic number, because the mean of its divisors is an integer number (103922400).

Almost surely, 2^1997981601 is an apocalyptic number.

1997981601 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1997981601 is a deficient number, since it is larger than the sum of its proper divisors (1327535199).

1997981601 is a wasteful number, since it uses less digits than its factorization.

1997981601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10949.

The product of its (nonzero) digits is 244944, while the sum is 51.

The square root of 1997981601 is about 44698.7874667759. The cubic root of 1997981601 is about 1259.4970700049.

The spelling of 1997981601 in words is "one billion, nine hundred ninety-seven million, nine hundred eighty-one thousand, six hundred one".