149778809 has 2 divisors, whose sum is σ = 149778810. Its totient is φ = 149778808.

The previous prime is 149778773. The next prime is 149778841. The reversal of 149778809 is 908877941.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 106915600 + 42863209 = 10340^2 + 6547^2 .

It is an emirp because it is prime and its reverse (908877941) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 149778809 - 2²⁴ = 133001593 is a prime.

It is a super-3 number, since 3×149778809³ (a number of 26 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (149778869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 74889404 + 74889405.

It is an arithmetic number, because the mean of its divisors is an integer number (74889405).

Almost surely, 2^149778809 is an apocalyptic number.

It is an amenable number.

149778809 is a deficient number, since it is larger than the sum of its proper divisors (1).

149778809 is an equidigital number, since it uses as much as digits as its factorization.

149778809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1016064, while the sum is 53.

The square root of 149778809 is about 12238.4152977418. The cubic root of 149778809 is about 531.0679888780.

The spelling of 149778809 in words is "one hundred forty-nine million, seven hundred seventy-eight thousand, eight hundred nine".