206821353540 has 24 divisors (see below), whose sum is σ = 579099790080. Its totient is φ = 55152360928.

The previous prime is 206821353533. The next prime is 206821353547. The reversal of 206821353540 is 45353128602.

It is a happy number.

206821353540 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (206821353533) and next prime (206821353547).

It is not an unprimeable number, because it can be changed into a prime (206821353547) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1723511220 + ... + 1723511339.

It is an arithmetic number, because the mean of its divisors is an integer number (24129157920).

Almost surely, 2^206821353540 is an apocalyptic number.

206821353540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

206821353540 is an abundant number, since it is smaller than the sum of its proper divisors (372278436540).

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

206821353540 is a wasteful number, since it uses less digits than its factorization.

206821353540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3447022571 (or 3447022569 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 39.

The spelling of 206821353540 in words is "two hundred six billion, eight hundred twenty-one million, three hundred fifty-three thousand, five hundred forty".