1997257626 has 96 divisors (see below), whose sum is σ = 5368516608. Its totient is φ = 522547200.

The previous prime is 1997257609. The next prime is 1997257627. The reversal of 1997257626 is 6267527991.

1997257626 is a `hidden beast` number, since 1 + 9 + 9 + 7 + 2 + 5 + 7 + 626 = 666.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1997257627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 203226 + ... + 212826.

It is an arithmetic number, because the mean of its divisors is an integer number (55922048).

Almost surely, 2^1997257626 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1997257626, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2684258304).

1997257626 is an abundant number, since it is smaller than the sum of its proper divisors (3371258982).

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

1997257626 is a wasteful number, since it uses less digits than its factorization.

1997257626 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9756 (or 9753 counting only the distinct ones).

The product of its digits is 2857680, while the sum is 54.

The square root of 1997257626 is about 44690.6883589859. The cubic root of 1997257626 is about 1259.3449240343.

The spelling of 1997257626 in words is "one billion, nine hundred ninety-seven million, two hundred fifty-seven thousand, six hundred twenty-six".