20989357 has 4 divisors (see below), whose sum is σ = 22094080. Its totient is φ = 19884636.

The previous prime is 20989349. The next prime is 20989391. The reversal of 20989357 is 75398902.

It is a happy number.

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: 75398902 = 2 ⋅37699451.

It is a cyclic number.

It is not a de Polignac number, because 20989357 - 2³ = 20989349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20989337) 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, 552333 + ... + 552370.

It is an arithmetic number, because the mean of its divisors is an integer number (5523520).

Almost surely, 2^20989357 is an apocalyptic number.

It is an amenable number.

20989357 is a deficient number, since it is larger than the sum of its proper divisors (1104723).

20989357 is a wasteful number, since it uses less digits than its factorization.

20989357 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1104722.

The product of its (nonzero) digits is 136080, while the sum is 43.

The square root of 20989357 is about 4581.4143012830. The cubic root of 20989357 is about 275.8458014604.

The spelling of 20989357 in words is "twenty million, nine hundred eighty-nine thousand, three hundred fifty-seven".