318149021 has 4 divisors (see below), whose sum is σ = 318561372. Its totient is φ = 317736672.

The previous prime is 318149017. The next prime is 318149023. The reversal of 318149021 is 120941813.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120941813 = 53 ⋅2281921.

It can be written as a sum of positive squares in 2 ways, for example, as 125328025 + 192820996 = 11195^2 + 13886^2 .

It is a cyclic number.

It is not a de Polignac number, because 318149021 - 2² = 318149017 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 (318149023) 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, 205016 + ... + 206561.

It is an arithmetic number, because the mean of its divisors is an integer number (79640343).

Almost surely, 2^318149021 is an apocalyptic number.

It is an amenable number.

318149021 is a deficient number, since it is larger than the sum of its proper divisors (412351).

318149021 is an equidigital number, since it uses as much as digits as its factorization.

318149021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 412350.

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

The square root of 318149021 is about 17836.7323520874. The cubic root of 318149021 is about 682.6690236911.

The spelling of 318149021 in words is "three hundred eighteen million, one hundred forty-nine thousand, twenty-one".