20398770 has 128 divisors (see below), whose sum is σ = 63866880. Its totient is φ = 4536000.

The previous prime is 20398757. The next prime is 20398787. The reversal of 20398770 is 7789302.

20398770 = 840² + 841² + ... + 867².

It is a super-2 number, since 2×20398770² = 832219635025800, which contains 22 as substring.

It is a congruent number.

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, 81145 + ... + 81395.

It is an arithmetic number, because the mean of its divisors is an integer number (498960).

Almost surely, 2^20398770 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20398770, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31933440).

20398770 is an abundant number, since it is smaller than the sum of its proper divisors (43468110).

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

20398770 is a wasteful number, since it uses less digits than its factorization.

20398770 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 317 (or 311 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 36.

The square root of 20398770 is about 4516.4997509133. The cubic root of 20398770 is about 273.2339499221.

The spelling of 20398770 in words is "twenty million, three hundred ninety-eight thousand, seven hundred seventy".