1821261 has 32 divisors (see below), whose sum is σ = 2878848. Its totient is φ = 1013760.

The previous prime is 1821257. The next prime is 1821263. The reversal of 1821261 is 1621281.

It is not a de Polignac number, because 1821261 - 2² = 1821257 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1821263) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 27150 + ... + 27216.

It is an arithmetic number, because the mean of its divisors is an integer number (89964).

2^1821261 is an apocalyptic number.

It is an amenable number.

1821261 is a deficient number, since it is larger than the sum of its proper divisors (1057587).

1821261 is a wasteful number, since it uses less digits than its factorization.

1821261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141.

The product of its digits is 192, while the sum is 21.

The square root of 1821261 is about 1349.5410330924. The cubic root of 1821261 is about 122.1211061143.

The spelling of 1821261 in words is "one million, eight hundred twenty-one thousand, two hundred sixty-one".