2861921 has 2 divisors, whose sum is σ = 2861922. Its totient is φ = 2861920.

The previous prime is 2861917. The next prime is 2861927. The reversal of 2861921 is 1291682.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2768896 + 93025 = 1664^2 + 305^2 .

It is a cyclic number.

It is not a de Polignac number, because 2861921 - 2² = 2861917 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is equal to p₂₀₇₅₇₈ and since 2861921 and 207578 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (2861927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1430960 + 1430961.

It is an arithmetic number, because the mean of its divisors is an integer number (1430961).

2^2861921 is an apocalyptic number.

It is an amenable number.

2861921 is a deficient number, since it is larger than the sum of its proper divisors (1).

2861921 is an equidigital number, since it uses as much as digits as its factorization.

2861921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 29.

The square root of 2861921 is about 1691.7213127463. The cubic root of 2861921 is about 141.9773983733.

The spelling of 2861921 in words is "two million, eight hundred sixty-one thousand, nine hundred twenty-one".