20819550 has 24 divisors (see below), whose sum is σ = 51632856. Its totient is φ = 5551840.

The previous prime is 20819521. The next prime is 20819563. The reversal of 20819550 is 5591802.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 69249 + ... + 69548.

It is an arithmetic number, because the mean of its divisors is an integer number (2151369).

Almost surely, 2^20819550 is an apocalyptic number.

20819550 is an abundant number, since it is smaller than the sum of its proper divisors (30813306).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20819550 is a wasteful number, since it uses less digits than its factorization.

20819550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138812 (or 138807 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 30.

The square root of 20819550 is about 4562.8445075413. The cubic root of 20819550 is about 275.0999086020.

The spelling of 20819550 in words is "twenty million, eight hundred nineteen thousand, five hundred fifty".