1491988797 has 18 divisors (see below), whose sum is σ = 2321521566. Its totient is φ = 917889840.

The previous prime is 1491988783. The next prime is 1491988837. The reversal of 1491988797 is 7978891941.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 1032915321 + 459073476 = 32139^2 + 21426^2 .

It is not a de Polignac number, because 1491988797 - 2⁶ = 1491988733 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1491988717) 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 17 ways as a sum of consecutive naturals, for example, 416022 + ... + 419592.

Almost surely, 2^1491988797 is an apocalyptic number.

It is an amenable number.

1491988797 is a deficient number, since it is larger than the sum of its proper divisors (829532769).

1491988797 is an frugal number, since it uses more digits than its factorization.

1491988797 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7161 (or 3587 counting only the distinct ones).

The product of its digits is 9144576, while the sum is 63.

The square root of 1491988797 is about 38626.2708140457. The cubic root of 1491988797 is about 1142.6727063760.

The spelling of 1491988797 in words is "one billion, four hundred ninety-one million, nine hundred eighty-eight thousand, seven hundred ninety-seven".