1997805888 has 84 divisors (see below), whose sum is σ = 6166861428. Its totient is φ = 614707200.

The previous prime is 1997805883. The next prime is 1997805907. The reversal of 1997805888 is 8885087991.

It can be written as a sum of positive squares in 2 ways, for example, as 267911424 + 1729894464 = 16368^2 + 41592^2 .

It is a super-2 number, since 2×1997805888² = 7982456732254937088, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1997805883) 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, 125913 + ... + 140888.

It is an arithmetic number, because the mean of its divisors is an integer number (73415017).

Almost surely, 2^1997805888 is an apocalyptic number.

1997805888 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1997805888 is an abundant number, since it is smaller than the sum of its proper divisors (4169055540).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1997805888 is a wasteful number, since it uses less digits than its factorization.

1997805888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266832 (or 266819 counting only the distinct ones).

The product of its (nonzero) digits is 11612160, while the sum is 63.

The square root of 1997805888 is about 44696.8219004439. The cubic root of 1997805888 is about 1259.4601466591.

It can be divided in two parts, 199 and 7805888, that added together give a palindrome (7806087).

The spelling of 1997805888 in words is "one billion, nine hundred ninety-seven million, eight hundred five thousand, eight hundred eighty-eight".