1621636 has 12 divisors (see below), whose sum is σ = 2914828. Its totient is φ = 788832.

The previous prime is 1621621. The next prime is 1621637. The reversal of 1621636 is 6361261.

It can be written as a sum of positive squares in 2 ways, for example, as 1254400 + 367236 = 1120^2 + 606^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1621636.

It is not an unprimeable number, because it can be changed into a prime (1621637) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5331 + ... + 5626.

2^1621636 is an apocalyptic number.

It is an amenable number.

1621636 is a deficient number, since it is larger than the sum of its proper divisors (1293192).

1621636 is a wasteful number, since it uses less digits than its factorization.

1621636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10998 (or 10996 counting only the distinct ones).

The product of its digits is 1296, while the sum is 25.

The square root of 1621636 is about 1273.4347254571. The cubic root of 1621636 is about 117.4855512639.

Adding to 1621636 its reverse (6361261), we get a palindrome (7982897).

The spelling of 1621636 in words is "one million, six hundred twenty-one thousand, six hundred thirty-six".