20434890 has 128 divisors (see below), whose sum is σ = 60014592. Its totient is φ = 4354560.

The previous prime is 20434873. The next prime is 20434913. The reversal of 20434890 is 9843402.

It is a happy number.

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

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 279894 + ... + 279966.

It is an arithmetic number, because the mean of its divisors is an integer number (468864).

Almost surely, 2^20434890 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20434890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30007296).

20434890 is an abundant number, since it is smaller than the sum of its proper divisors (39579702).

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

20434890 is a wasteful number, since it uses less digits than its factorization.

20434890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164.

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 20434890 is about 4520.4966541299. The cubic root of 20434890 is about 273.3951261576.

The spelling of 20434890 in words is "twenty million, four hundred thirty-four thousand, eight hundred ninety".