20751689 has 4 divisors (see below), whose sum is σ = 23716224. Its totient is φ = 17787156.

The previous prime is 20751683. The next prime is 20751691. The reversal of 20751689 is 98615702.

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.

It is a cyclic number.

It is not a de Polignac number, because 20751689 - 2²⁰ = 19703113 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20751683) 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, 1482257 + ... + 1482270.

It is an arithmetic number, because the mean of its divisors is an integer number (5929056).

Almost surely, 2^20751689 is an apocalyptic number.

It is an amenable number.

20751689 is a deficient number, since it is larger than the sum of its proper divisors (2964535).

20751689 is an equidigital number, since it uses as much as digits as its factorization.

20751689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2964534.

The product of its (nonzero) digits is 30240, while the sum is 38.

The square root of 20751689 is about 4555.4021776348. The cubic root of 20751689 is about 274.8006886381.

The spelling of 20751689 in words is "twenty million, seven hundred fifty-one thousand, six hundred eighty-nine".