149961781 has 2 divisors, whose sum is σ = 149961782. Its totient is φ = 149961780.

The previous prime is 149961767. The next prime is 149961821. The reversal of 149961781 is 187169941.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 100821681 + 49140100 = 10041^2 + 7010^2 .

It is a cyclic number.

It is not a de Polignac number, because 149961781 - 2²⁵ = 116407349 is a prime.

It is a super-2 number, since 2×149961781² = 44977071521383922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (149961701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 74980890 + 74980891.

It is an arithmetic number, because the mean of its divisors is an integer number (74980891).

Almost surely, 2^149961781 is an apocalyptic number.

It is an amenable number.

149961781 is a deficient number, since it is larger than the sum of its proper divisors (1).

149961781 is an equidigital number, since it uses as much as digits as its factorization.

149961781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108864, while the sum is 46.

The square root of 149961781 is about 12245.8883303744. Note that the first 3 decimals coincide. The cubic root of 149961781 is about 531.2841543716.

The spelling of 149961781 in words is "one hundred forty-nine million, nine hundred sixty-one thousand, seven hundred eighty-one".