1900645 has 4 divisors (see below), whose sum is σ = 2280780. Its totient is φ = 1520512.

The previous prime is 1900621. The next prime is 1900667. The reversal of 1900645 is 5460091.

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

It can be written as a sum of positive squares in 2 ways, for example, as 538756 + 1361889 = 734^2 + 1167^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1900645 is a prime.

It is a super-2 number, since 2×1900645² = 7224902832050, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 190060 + ... + 190069.

It is an arithmetic number, because the mean of its divisors is an integer number (570195).

2^1900645 is an apocalyptic number.

It is an amenable number.

1900645 is a deficient number, since it is larger than the sum of its proper divisors (380135).

1900645 is an equidigital number, since it uses as much as digits as its factorization.

1900645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 380134.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 1900645 is about 1378.6388214467. The cubic root of 1900645 is about 123.8702466879.

The spelling of 1900645 in words is "one million, nine hundred thousand, six hundred forty-five".