401861 has 2 divisors, whose sum is σ = 401862. Its totient is φ = 401860.

The previous prime is 401839. The next prime is 401867. The reversal of 401861 is 168104.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 390625 + 11236 = 625^2 + 106^2 .

It is a cyclic number.

It is not a de Polignac number, because 401861 - 2¹⁰ = 400837 is a prime.

It is a super-2 number, since 2×401861² = 322984526642, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (401867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200930 + 200931.

It is an arithmetic number, because the mean of its divisors is an integer number (200931).

2⁴⁰¹⁸⁶¹ is an apocalyptic number.

401861 is the 284-th centered decagonal number.

It is an amenable number.

401861 is a deficient number, since it is larger than the sum of its proper divisors (1).

401861 is an equidigital number, since it uses as much as digits as its factorization.

401861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 401861 is about 633.9250744370. The cubic root of 401861 is about 73.7947195983.

Adding to 401861 its reverse (168104), we get a palindrome (569965).

The spelling of 401861 in words is "four hundred one thousand, eight hundred sixty-one".