149171821 has 4 divisors (see below), whose sum is σ = 157946652. Its totient is φ = 140396992.

The previous prime is 149171807. The next prime is 149171837. The reversal of 149171821 is 128171941.

149171821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 139499721 + 9672100 = 11811^2 + 3110^2 .

It is a cyclic number.

It is not a de Polignac number, because 149171821 - 2¹¹ = 149169773 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (149171851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4387390 + ... + 4387423.

It is an arithmetic number, because the mean of its divisors is an integer number (39486663).

Almost surely, 2^149171821 is an apocalyptic number.

It is an amenable number.

149171821 is a deficient number, since it is larger than the sum of its proper divisors (8774831).

149171821 is an equidigital number, since it uses as much as digits as its factorization.

149171821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8774830.

The product of its digits is 4032, while the sum is 34.

The square root of 149171821 is about 12213.5916502886. The cubic root of 149171821 is about 530.3496221699.

The spelling of 149171821 in words is "one hundred forty-nine million, one hundred seventy-one thousand, eight hundred twenty-one".