20319551 has 4 divisors (see below), whose sum is σ = 23222352. Its totient is φ = 17416752.

The previous prime is 20319503. The next prime is 20319581. The reversal of 20319551 is 15591302.

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

It is a cyclic number.

It is not a de Polignac number, because 20319551 - 2⁶ = 20319487 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20319551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20319581) 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, 1451390 + ... + 1451403.

It is an arithmetic number, because the mean of its divisors is an integer number (5805588).

Almost surely, 2^20319551 is an apocalyptic number.

20319551 is a deficient number, since it is larger than the sum of its proper divisors (2902801).

20319551 is an equidigital number, since it uses as much as digits as its factorization.

20319551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2902800.

The product of its (nonzero) digits is 1350, while the sum is 26.

The square root of 20319551 is about 4507.7212646746. The cubic root of 20319551 is about 272.8797880308.

The spelling of 20319551 in words is "twenty million, three hundred nineteen thousand, five hundred fifty-one".