149031821 has 2 divisors, whose sum is σ = 149031822. Its totient is φ = 149031820.

The previous prime is 149031797. The next prime is 149031823. The reversal of 149031821 is 128130941.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 144240100 + 4791721 = 12010^2 + 2189^2 .

It is an emirp because it is prime and its reverse (128130941) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 149031821 - 2²⁶ = 81922957 is a prime.

It is a Sophie Germain prime.

Together with 149031823, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (149031823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 74515910 + 74515911.

It is an arithmetic number, because the mean of its divisors is an integer number (74515911).

Almost surely, 2^149031821 is an apocalyptic number.

It is an amenable number.

149031821 is a deficient number, since it is larger than the sum of its proper divisors (1).

149031821 is an equidigital number, since it uses as much as digits as its factorization.

149031821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 149031821 is about 12207.8589850964. The cubic root of 149031821 is about 530.1836565368.

The spelling of 149031821 in words is "one hundred forty-nine million, thirty-one thousand, eight hundred twenty-one".