391166437489 has 9 divisors (see below), whose sum is σ = 397722916929. Its totient is φ = 384716346960.

The previous prime is 391166437483. The next prime is 391166437507. The reversal of 391166437489 is 984734661193.

The square root of 391166437489 is 625433.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 290418599025 + 100747838464 = 538905^2 + 317408^2 .

It is not a de Polignac number, because 391166437489 - 2³ = 391166437481 is a prime.

It is a super-2 number, since 2×391166437489² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (61).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (391166437481) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 38146287 + ... + 38156539.

Almost surely, 2^391166437489 is an apocalyptic number.

391166437489 is the 625433-rd square number.

391166437489 is the 312717-th centered octagonal number.

It is an amenable number.

391166437489 is a deficient number, since it is larger than the sum of its proper divisors (6556479440).

391166437489 is an frugal number, since it uses more digits than its factorization.

391166437489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20628 (or 10314 counting only the distinct ones).

The product of its digits is 23514624, while the sum is 61.

The spelling of 391166437489 in words is "three hundred ninety-one billion, one hundred sixty-six million, four hundred thirty-seven thousand, four hundred eighty-nine".