21115515550206 has 64 divisors (see below), whose sum is σ = 52658498027520. Its totient is φ = 5483838776160.

The previous prime is 21115515550193. The next prime is 21115515550219. The reversal of 21115515550206 is 60205551551112.

It is an interprime number because it is at equal distance from previous prime (21115515550193) and next prime (21115515550219).

It is a congruent number.

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, 612415 + ... + 6527333.

It is an arithmetic number, because the mean of its divisors is an integer number (822789031680).

Almost surely, 2^{21115515550206} is an apocalyptic number.

21115515550206 is an abundant number, since it is smaller than the sum of its proper divisors (31542982477314).

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

21115515550206 is a wasteful number, since it uses less digits than its factorization.

21115515550206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5922669.

The product of its (nonzero) digits is 75000, while the sum is 39.

The spelling of 21115515550206 in words is "twenty-one trillion, one hundred fifteen billion, five hundred fifteen million, five hundred fifty thousand, two hundred six".