20347645 has 4 divisors (see below), whose sum is σ = 24417180. Its totient is φ = 16278112.

The previous prime is 20347633. The next prime is 20347661. The reversal of 20347645 is 54674302.

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 8139609 + 12208036 = 2853^2 + 3494^2 .

It is a cyclic number.

It is not a de Polignac number, because 20347645 - 2⁷ = 20347517 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2034760 + ... + 2034769.

It is an arithmetic number, because the mean of its divisors is an integer number (6104295).

Almost surely, 2^20347645 is an apocalyptic number.

It is an amenable number.

20347645 is a deficient number, since it is larger than the sum of its proper divisors (4069535).

20347645 is an equidigital number, since it uses as much as digits as its factorization.

20347645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4069534.

The product of its (nonzero) digits is 20160, while the sum is 31.

The square root of 20347645 is about 4510.8363969446. The cubic root of 20347645 is about 273.0054921587.

The spelling of 20347645 in words is "twenty million, three hundred forty-seven thousand, six hundred forty-five".