1621712844 has 18 divisors (see below), whose sum is σ = 4099329780. Its totient is φ = 540570936.

The previous prime is 1621712837. The next prime is 1621712867. The reversal of 1621712844 is 4482171261.

It is a happy number.

1621712844 is a `hidden beast` number, since 1 + 621 + 7 + 1 + 28 + 4 + 4 = 666.

1621712844 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 45047579 = 1621712844 / (1 + 6 + 2 + 1 + 7 + 1 + 2 + 8 + 4 + 4).

It is a junction number, because it is equal to n+sod(n) for n = 1621712799 and 1621712808.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 22523754 + ... + 22523825.

Almost surely, 2^1621712844 is an apocalyptic number.

It is an amenable number.

1621712844 is an abundant number, since it is smaller than the sum of its proper divisors (2477616936).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1621712844 is a wasteful number, since it uses less digits than its factorization.

1621712844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45047589 (or 45047584 counting only the distinct ones).

The product of its digits is 21504, while the sum is 36.

The square root of 1621712844 is about 40270.4959492679. The cubic root of 1621712844 is about 1174.8740698599.

The spelling of 1621712844 in words is "one billion, six hundred twenty-one million, seven hundred twelve thousand, eight hundred forty-four".