20541551 has 4 divisors (see below), whose sum is σ = 20553504. Its totient is φ = 20529600.

The previous prime is 20541523. The next prime is 20541557. The reversal of 20541551 is 15514502.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 15514502 = 2 ⋅7757251.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20541551 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 (20541557) 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, 2855 + ... + 7016.

It is an arithmetic number, because the mean of its divisors is an integer number (5138376).

Almost surely, 2^20541551 is an apocalyptic number.

20541551 is a deficient number, since it is larger than the sum of its proper divisors (11953).

20541551 is an equidigital number, since it uses as much as digits as its factorization.

20541551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11952.

The product of its (nonzero) digits is 1000, while the sum is 23.

The square root of 20541551 is about 4532.2787866591. The cubic root of 20541551 is about 273.8699677816.

The spelling of 20541551 in words is "twenty million, five hundred forty-one thousand, five hundred fifty-one".