20308890 has 64 divisors (see below), whose sum is σ = 56335104. Its totient is φ = 4589568.

The previous prime is 20308879. The next prime is 20308901. The reversal of 20308890 is 9880302.

It is an interprime number because it is at equal distance from previous prime (20308879) and next prime (20308901).

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 31 ways as a sum of consecutive naturals, for example, 19872 + ... + 20868.

It is an arithmetic number, because the mean of its divisors is an integer number (880236).

Almost surely, 2^20308890 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20308890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28167552).

20308890 is an abundant number, since it is smaller than the sum of its proper divisors (36026214).

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

20308890 is a wasteful number, since it uses less digits than its factorization.

20308890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1111.

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 20308890 is about 4506.5385829925. The cubic root of 20308890 is about 272.8320559992.

The spelling of 20308890 in words is "twenty million, three hundred eight thousand, eight hundred ninety".