20605451 has 4 divisors (see below), whose sum is σ = 20631312. Its totient is φ = 20579592.

The previous prime is 20605397. The next prime is 20605463. The reversal of 20605451 is 15450602.

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 20605451 - 2²² = 16411147 is a prime.

It is a super-2 number, since 2×20605451² = 849169221826802, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20665451) 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, 11696 + ... + 13341.

It is an arithmetic number, because the mean of its divisors is an integer number (5157828).

Almost surely, 2^20605451 is an apocalyptic number.

20605451 is a deficient number, since it is larger than the sum of its proper divisors (25861).

20605451 is an equidigital number, since it uses as much as digits as its factorization.

20605451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25860.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 20605451 is about 4539.3227468423. The cubic root of 20605451 is about 274.1536558015.

The spelling of 20605451 in words is "twenty million, six hundred five thousand, four hundred fifty-one".