20351797 has 4 divisors (see below), whose sum is σ = 20367916. Its totient is φ = 20335680.

The previous prime is 20351791. The next prime is 20351801. The reversal of 20351797 is 79715302.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79715302 = 2 ⋅39857651.

It can be written as a sum of positive squares in 2 ways, for example, as 13586596 + 6765201 = 3686^2 + 2601^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20351797 is a prime.

It is a super-2 number, since 2×20351797² = 828391282258418, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20351791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5988 + ... + 8749.

It is an arithmetic number, because the mean of its divisors is an integer number (5091979).

Almost surely, 2^20351797 is an apocalyptic number.

It is an amenable number.

20351797 is a deficient number, since it is larger than the sum of its proper divisors (16119).

20351797 is a wasteful number, since it uses less digits than its factorization.

20351797 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16118.

The product of its (nonzero) digits is 13230, while the sum is 34.

The square root of 20351797 is about 4511.2965985402. The cubic root of 20351797 is about 273.0240601013.

The spelling of 20351797 in words is "twenty million, three hundred fifty-one thousand, seven hundred ninety-seven".