399018261 has 4 divisors (see below), whose sum is σ = 532024352. Its totient is φ = 266012172.

The previous prime is 399018253. The next prime is 399018281. The reversal of 399018261 is 162810993.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 399018261 - 2³ = 399018253 is a prime.

It is a super-2 number, since 2×399018261² = 318431145222928242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399018281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66503041 + ... + 66503046.

It is an arithmetic number, because the mean of its divisors is an integer number (133006088).

Almost surely, 2^399018261 is an apocalyptic number.

It is an amenable number.

399018261 is a deficient number, since it is larger than the sum of its proper divisors (133006091).

399018261 is a wasteful number, since it uses less digits than its factorization.

399018261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133006090.

The product of its (nonzero) digits is 23328, while the sum is 39.

The square root of 399018261 is about 19975.4414469368. The cubic root of 399018261 is about 736.2030130002.

The spelling of 399018261 in words is "three hundred ninety-nine million, eighteen thousand, two hundred sixty-one".