16815149 has 4 divisors (see below), whose sum is σ = 18108636. Its totient is φ = 15521664.

The previous prime is 16815137. The next prime is 16815173. The reversal of 16815149 is 94151861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 94151861 = 569 ⋅165469.

It can be written as a sum of positive squares in 2 ways, for example, as 3258025 + 13557124 = 1805^2 + 3682^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16815149 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16815109) 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, 646724 + ... + 646749.

It is an arithmetic number, because the mean of its divisors is an integer number (4527159).

Almost surely, 2^16815149 is an apocalyptic number.

It is an amenable number.

16815149 is a deficient number, since it is larger than the sum of its proper divisors (1293487).

16815149 is a wasteful number, since it uses less digits than its factorization.

16815149 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1293486.

The product of its digits is 8640, while the sum is 35.

The square root of 16815149 is about 4100.6278787522. The cubic root of 16815149 is about 256.1927919883.

The spelling of 16815149 in words is "sixteen million, eight hundred fifteen thousand, one hundred forty-nine".