2157631 has 16 divisors (see below), whose sum is σ = 2603008. Its totient is φ = 1749600.

The previous prime is 2157587. The next prime is 2157641. The reversal of 2157631 is 1367512.

It is a 7-Lehmer number, since φ(2157631) divides (2157631-1)⁷.

It is a cyclic number.

It is not a de Polignac number, because 2157631 - 2⁷ = 2157503 is a prime.

It is a super-2 number, since 2×2157631² = 9310743064322, which contains 22 as substring.

It is a d-powerful number, because it can be written as 2²¹ + 1 + 5³ + 7 + 6⁴ + 3¹⁰ + 1 .

It is a junction number, because it is equal to n+sod(n) for n = 2157596 and 2157605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2157641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13156 + ... + 13318.

It is an arithmetic number, because the mean of its divisors is an integer number (162688).

2^2157631 is an apocalyptic number.

2157631 is a deficient number, since it is larger than the sum of its proper divisors (445377).

2157631 is a wasteful number, since it uses less digits than its factorization.

2157631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 262.

The product of its digits is 1260, while the sum is 25.

The square root of 2157631 is about 1468.8876743986. The cubic root of 2157631 is about 129.2188061906.

The spelling of 2157631 in words is "two million, one hundred fifty-seven thousand, six hundred thirty-one".