146991681 has 6 divisors (see below), whose sum is σ = 212321330. Its totient is φ = 97994448.

The previous prime is 146991679. The next prime is 146991703. The reversal of 146991681 is 186199641.

It can be written as a sum of positive squares in only one way, i.e., 134096400 + 12895281 = 11580^2 + 3591^2 .

It is not a de Polignac number, because 146991681 - 2¹ = 146991679 is a prime.

It is a super-2 number, since 2×146991681² = 43213108566411522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (146999681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8166196 + ... + 8166213.

Almost surely, 2^146991681 is an apocalyptic number.

It is an amenable number.

146991681 is a deficient number, since it is larger than the sum of its proper divisors (65329649).

146991681 is a wasteful number, since it uses less digits than its factorization.

146991681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16332415 (or 16332412 counting only the distinct ones).

The product of its digits is 93312, while the sum is 45.

The square root of 146991681 is about 12124.0125783505. The cubic root of 146991681 is about 527.7532529061.

The spelling of 146991681 in words is "one hundred forty-six million, nine hundred ninety-one thousand, six hundred eighty-one".