2151405 has 12 divisors (see below), whose sum is σ = 3729180. Its totient is φ = 1147392.

The previous prime is 2151403. The next prime is 2151421. The reversal of 2151405 is 5041512.

It can be written as a sum of positive squares in 2 ways, for example, as 393129 + 1758276 = 627^2 + 1326^2 .

It is not a de Polignac number, because 2151405 - 2¹ = 2151403 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2151403) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 23860 + ... + 23949.

It is an arithmetic number, because the mean of its divisors is an integer number (310765).

2^2151405 is an apocalyptic number.

It is an amenable number.

2151405 is a deficient number, since it is larger than the sum of its proper divisors (1577775).

2151405 is a wasteful number, since it uses less digits than its factorization.

2151405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47820 (or 47817 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 2151405 is about 1466.7668526388. The cubic root of 2151405 is about 129.0943963850.

Adding to 2151405 its reverse (5041512), we get a palindrome (7192917).

It can be divided in two parts, 2151 and 405, that added together give a triangular number (2556 = T₇₁).

The spelling of 2151405 in words is "two million, one hundred fifty-one thousand, four hundred five".