401610661 has 2 divisors, whose sum is σ = 401610662. Its totient is φ = 401610660.

The previous prime is 401610637. The next prime is 401610667. The reversal of 401610661 is 166016104.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 392277636 + 9333025 = 19806^2 + 3055^2 .

It is a cyclic number.

It is not a de Polignac number, because 401610661 - 2⁹ = 401610149 is a prime.

It is a super-2 number, since 2×401610661² = 322582246057713842, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (401610667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200805330 + 200805331.

It is an arithmetic number, because the mean of its divisors is an integer number (200805331).

Almost surely, 2^401610661 is an apocalyptic number.

It is an amenable number.

401610661 is a deficient number, since it is larger than the sum of its proper divisors (1).

401610661 is an equidigital number, since it uses as much as digits as its factorization.

401610661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 401610661 is about 20040.2260715791. The cubic root of 401610661 is about 737.7939296074.

Adding to 401610661 its reverse (166016104), we get a palindrome (567626765).

The spelling of 401610661 in words is "four hundred one million, six hundred ten thousand, six hundred sixty-one".