501778381 has 8 divisors (see below), whose sum is σ = 545948984. Its totient is φ = 458403840.

The previous prime is 501778379. The next prime is 501778399. The reversal of 501778381 is 183877105.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 16281225 + 485497156 = 4035^2 + 22034^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 501778381 - 2¹ = 501778379 is a prime.

It is a super-2 number, since 2×501778381² = 503563087277962322, 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 (501779381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 197700 + ... + 200221.

It is an arithmetic number, because the mean of its divisors is an integer number (68243623).

Almost surely, 2^501778381 is an apocalyptic number.

It is an amenable number.

501778381 is a deficient number, since it is larger than the sum of its proper divisors (44170603).

501778381 is a wasteful number, since it uses less digits than its factorization.

501778381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398031.

The product of its (nonzero) digits is 47040, while the sum is 40.

The square root of 501778381 is about 22400.4102864211. The cubic root of 501778381 is about 794.6404138342.

The spelling of 501778381 in words is "five hundred one million, seven hundred seventy-eight thousand, three hundred eighty-one".