2198781 has 12 divisors (see below), whose sum is σ = 3420508. Its totient is φ = 1353024.

The previous prime is 2198767. The next prime is 2198783. The reversal of 2198781 is 1878912.

2198781 = T₃₉₀ + T₃₉₁ + ... + T₄₁₆.

It can be written as a sum of positive squares in 2 ways, for example, as 933156 + 1265625 = 966^2 + 1125^2 .

It is not a de Polignac number, because 2198781 - 2⁷ = 2198653 is a prime.

It is a super-2 number, since 2×2198781² = 9669275771922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2198783) 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, 9280 + ... + 9513.

2^2198781 is an apocalyptic number.

It is an amenable number.

2198781 is a deficient number, since it is larger than the sum of its proper divisors (1221727).

2198781 is a wasteful number, since it uses less digits than its factorization.

2198781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18812 (or 18809 counting only the distinct ones).

The product of its digits is 8064, while the sum is 36.

The square root of 2198781 is about 1482.8287156648. The cubic root of 2198781 is about 130.0351187172.

The spelling of 2198781 in words is "two million, one hundred ninety-eight thousand, seven hundred eighty-one".