2661631 has 6 divisors (see below), whose sum is σ = 3096240. Its totient is φ = 2281356.

The previous prime is 2661611. The next prime is 2661641. The reversal of 2661631 is 1361662.

It is not a de Polignac number, because 2661631 - 2⁹ = 2661119 is a prime.

It is a super-2 number, since 2×2661631² = 14168559160322, which contains 22 as substring.

It is a plaindrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 2661596 and 2661605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2661611) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 27111 + ... + 27208.

It is an arithmetic number, because the mean of its divisors is an integer number (516040).

2^2661631 is an apocalyptic number.

2661631 is a deficient number, since it is larger than the sum of its proper divisors (434609).

2661631 is an equidigital number, since it uses as much as digits as its factorization.

2661631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54333 (or 54326 counting only the distinct ones).

The product of its digits is 1296, while the sum is 25.

The square root of 2661631 is about 1631.4505815378. The cubic root of 2661631 is about 138.5849114616.

It can be divided in two parts, 266 and 1631, that multiplied together give a triangular number (433846 = T₉₃₁).

The spelling of 2661631 in words is "two million, six hundred sixty-one thousand, six hundred thirty-one".