20455890 has 128 divisors (see below), whose sum is σ = 61931520. Its totient is φ = 4209408.

The previous prime is 20455873. The next prime is 20455891. The reversal of 20455890 is 9855402.

20455890 = 31² + 32² + ... + 394².

It is not an unprimeable number, because it can be changed into a prime (20455891) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 161007 + ... + 161133.

It is an arithmetic number, because the mean of its divisors is an integer number (483840).

Almost surely, 2^20455890 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20455890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30965760).

20455890 is an abundant number, since it is smaller than the sum of its proper divisors (41475630).

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

20455890 is a wasteful number, since it uses less digits than its factorization.

20455890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216.

The product of its (nonzero) digits is 14400, while the sum is 33.

The square root of 20455890 is about 4522.8188113167. The cubic root of 20455890 is about 273.4887459761.

The spelling of 20455890 in words is "twenty million, four hundred fifty-five thousand, eight hundred ninety".