2121986 has 4 divisors (see below), whose sum is σ = 3182982. Its totient is φ = 1060992.

The previous prime is 2121979. The next prime is 2121989. The reversal of 2121986 is 6891212.

2121986 = 415² + 416² + ... + 426².

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 1890625 + 231361 = 1375^2 + 481^2 .

It is not an unprimeable number, because it can be changed into a prime (2121989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 530495 + ... + 530498.

2^2121986 is an apocalyptic number.

2121986 is a deficient number, since it is larger than the sum of its proper divisors (1060996).

2121986 is a wasteful number, since it uses less digits than its factorization.

2121986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1060995.

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

The square root of 2121986 is about 1456.7038134089. The cubic root of 2121986 is about 128.5032676928.

The spelling of 2121986 in words is "two million, one hundred twenty-one thousand, nine hundred eighty-six".