1620889 has 4 divisors (see below), whose sum is σ = 1655424. Its totient is φ = 1586356.

The previous prime is 1620887. The next prime is 1620893. The reversal of 1620889 is 9880261.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9880261 = 1721 ⋅5741.

It is a cyclic number.

It is not a de Polignac number, because 1620889 - 2¹ = 1620887 is a prime.

It is a Duffinian number.

1620889 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1620881) 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, 17197 + ... + 17290.

It is an arithmetic number, because the mean of its divisors is an integer number (413856).

2^1620889 is an apocalyptic number.

It is an amenable number.

1620889 is a deficient number, since it is larger than the sum of its proper divisors (34535).

1620889 is an equidigital number, since it uses as much as digits as its factorization.

1620889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34534.

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 1620889 is about 1273.1413904198. The cubic root of 1620889 is about 117.4675087468.

The spelling of 1620889 in words is "one million, six hundred twenty thousand, eight hundred eighty-nine".