2187621 has 8 divisors (see below), whose sum is σ = 3240960. Its totient is φ = 1458396.

The previous prime is 2187613. The next prime is 2187629. The reversal of 2187621 is 1267812.

It is an interprime number because it is at equal distance from previous prime (2187613) and next prime (2187629).

It is not a de Polignac number, because 2187621 - 2³ = 2187613 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 81023 = 2187621 / (2 + 1 + 8 + 7 + 6 + 2 + 1).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2187629) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40485 + ... + 40538.

It is an arithmetic number, because the mean of its divisors is an integer number (405120).

2^2187621 is an apocalyptic number.

It is an amenable number.

2187621 is a deficient number, since it is larger than the sum of its proper divisors (1053339).

2187621 is an equidigital number, since it uses as much as digits as its factorization.

2187621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81032 (or 81026 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 2187621 is about 1479.0608506752. The cubic root of 2187621 is about 129.8147459947.

The spelling of 2187621 in words is "two million, one hundred eighty-seven thousand, six hundred twenty-one".