1997981602 has 4 divisors (see below), whose sum is σ = 2996972406. Its totient is φ = 998990800.

The previous prime is 1997981591. The next prime is 1997981621. The reversal of 1997981602 is 2061897991.

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

It can be written as a sum of positive squares in only one way, i.e., 1971448801 + 26532801 = 44401^2 + 5151^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1997981602.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 499495399 + ... + 499495402.

Almost surely, 2^1997981602 is an apocalyptic number.

1997981602 is a deficient number, since it is larger than the sum of its proper divisors (998990804).

1997981602 is an equidigital number, since it uses as much as digits as its factorization.

1997981602 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 998990803.

The product of its (nonzero) digits is 489888, while the sum is 52.

The square root of 1997981602 is about 44698.7874779619. The cubic root of 1997981602 is about 1259.4970702150.

The spelling of 1997981602 in words is "one billion, nine hundred ninety-seven million, nine hundred eighty-one thousand, six hundred two".