20413551 has 4 divisors (see below), whose sum is σ = 27218072. Its totient is φ = 13609032.

The previous prime is 20413537. The next prime is 20413559. The reversal of 20413551 is 15531402.

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

It is not a de Polignac number, because 20413551 - 2¹⁸ = 20151407 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 (20413559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3402256 + ... + 3402261.

It is an arithmetic number, because the mean of its divisors is an integer number (6804518).

Almost surely, 2^20413551 is an apocalyptic number.

20413551 is a deficient number, since it is larger than the sum of its proper divisors (6804521).

20413551 is an equidigital number, since it uses as much as digits as its factorization.

20413551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6804520.

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 20413551 is about 4518.1357881321. The cubic root of 20413551 is about 273.2999293239.

Adding to 20413551 its reverse (15531402), we get a palindrome (35944953).

The spelling of 20413551 in words is "twenty million, four hundred thirteen thousand, five hundred fifty-one".