20603551 has 4 divisors (see below), whose sum is σ = 20662272. Its totient is φ = 20544832.

The previous prime is 20603533. The next prime is 20603563. The reversal of 20603551 is 15530602.

It is a happy number.

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 20603551 - 2⁵ = 20603519 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 (20603501) 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, 28831 + ... + 29536.

It is an arithmetic number, because the mean of its divisors is an integer number (5165568).

Almost surely, 2^20603551 is an apocalyptic number.

20603551 is a deficient number, since it is larger than the sum of its proper divisors (58721).

20603551 is an equidigital number, since it uses as much as digits as its factorization.

20603551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58720.

The product of its (nonzero) digits is 900, while the sum is 22.

The square root of 20603551 is about 4539.1134596967. The cubic root of 20603551 is about 274.1452291000.

The spelling of 20603551 in words is "twenty million, six hundred three thousand, five hundred fifty-one".