20998240 has 48 divisors (see below), whose sum is σ = 50963472. Its totient is φ = 8169984.

The previous prime is 20998223. The next prime is 20998259. The reversal of 20998240 is 4289902.

20998240 = 541² + 542² + ... + 604².

It is a junction number, because it is equal to n+sod(n) for n = 20998196 and 20998205.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4147 + ... + 7693.

It is an arithmetic number, because the mean of its divisors is an integer number (1061739).

Almost surely, 2^20998240 is an apocalyptic number.

20998240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20998240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25481736).

20998240 is an abundant number, since it is smaller than the sum of its proper divisors (29965232).

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

20998240 is a wasteful number, since it uses less digits than its factorization.

20998240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3599 (or 3591 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 20998240 is about 4582.3836591887. The cubic root of 20998240 is about 275.8847099521.

The spelling of 20998240 in words is "twenty million, nine hundred ninety-eight thousand, two hundred forty".