1620986 has 4 divisors (see below), whose sum is σ = 2431482. Its totient is φ = 810492.

The previous prime is 1620977. The next prime is 1620989. The reversal of 1620986 is 6890261.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6890261 = 7 ⋅984323.

It can be written as a sum of positive squares in only one way, i.e., 1515361 + 105625 = 1231^2 + 325^2 .

It is a super-2 number, since 2×1620986² = 5255191224392, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1620989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 405245 + ... + 405248.

2^1620986 is an apocalyptic number.

1620986 is a deficient number, since it is larger than the sum of its proper divisors (810496).

1620986 is an equidigital number, since it uses as much as digits as its factorization.

1620986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 810495.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 1620986 is about 1273.1794845975. The cubic root of 1620986 is about 117.4698519303.

The spelling of 1620986 in words is "one million, six hundred twenty thousand, nine hundred eighty-six".