20400451 has 4 divisors (see below), whose sum is σ = 20514600. Its totient is φ = 20286304.

The previous prime is 20400439. The next prime is 20400463. The reversal of 20400451 is 15400402.

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

It is an interprime number because it is at equal distance from previous prime (20400439) and next prime (20400463).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20400451 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20400421) 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, 56806 + ... + 57163.

It is an arithmetic number, because the mean of its divisors is an integer number (5128650).

Almost surely, 2^20400451 is an apocalyptic number.

20400451 is a deficient number, since it is larger than the sum of its proper divisors (114149).

20400451 is a wasteful number, since it uses less digits than its factorization.

20400451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114148.

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 20400451 is about 4516.6858425177. The cubic root of 20400451 is about 273.2414551728.

Adding to 20400451 its reverse (15400402), we get a palindrome (35800853).

The spelling of 20400451 in words is "twenty million, four hundred thousand, four hundred fifty-one".