2158621 has 2 divisors, whose sum is σ = 2158622. Its totient is φ = 2158620.

The previous prime is 2158603. The next prime is 2158627. The reversal of 2158621 is 1268512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1276900 + 881721 = 1130^2 + 939^2 .

It is a cyclic number.

It is not a de Polignac number, because 2158621 - 2⁵ = 2158589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2158627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1079310 + 1079311.

It is an arithmetic number, because the mean of its divisors is an integer number (1079311).

2^2158621 is an apocalyptic number.

It is an amenable number.

2158621 is a deficient number, since it is larger than the sum of its proper divisors (1).

2158621 is an equidigital number, since it uses as much as digits as its factorization.

2158621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 960, while the sum is 25.

The square root of 2158621 is about 1469.2246254402. The cubic root of 2158621 is about 129.2385666065.

It can be divided in two parts, 215 and 8621, that added together give a square (8836 = 94²).

The spelling of 2158621 in words is "two million, one hundred fifty-eight thousand, six hundred twenty-one".