390057781 has 4 divisors (see below), whose sum is σ = 390099564. Its totient is φ = 390016000.

The previous prime is 390057751. The next prime is 390057847. The reversal of 390057781 is 187750093.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 187750093 = 2621 ⋅71633.

It can be written as a sum of positive squares in 2 ways, for example, as 248566756 + 141491025 = 15766^2 + 11895^2 .

It is a cyclic number.

It is not a de Polignac number, because 390057781 - 2¹⁹ = 389533493 is a prime.

It is a super-2 number, since 2×390057781² = 304290145037287922, 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 (390057751) 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, 231 + ... + 27931.

It is an arithmetic number, because the mean of its divisors is an integer number (97524891).

Almost surely, 2^390057781 is an apocalyptic number.

It is an amenable number.

390057781 is a deficient number, since it is larger than the sum of its proper divisors (41783).

390057781 is a wasteful number, since it uses less digits than its factorization.

390057781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41782.

The product of its (nonzero) digits is 52920, while the sum is 40.

The square root of 390057781 is about 19749.8805312842. The cubic root of 390057781 is about 730.6504373580.

The spelling of 390057781 in words is "three hundred ninety million, fifty-seven thousand, seven hundred eighty-one".