21155705705662 has 24 divisors (see below), whose sum is σ = 34881017862600. Its totient is φ = 9616139018640.

The previous prime is 21155705705579. The next prime is 21155705705713. The reversal of 21155705705662 is 26650750755112.

It is a happy number.

It is a hoax number, since the sum of its digits (52) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 29819289 + ... + 30520507.

It is an arithmetic number, because the mean of its divisors is an integer number (1453375744275).

Almost surely, 2^{21155705705662} is an apocalyptic number.

21155705705662 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21155705705662 is a deficient number, since it is larger than the sum of its proper divisors (13725312156938).

21155705705662 is a wasteful number, since it uses less digits than its factorization.

21155705705662 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 825912 (or 825901 counting only the distinct ones).

The product of its (nonzero) digits is 4410000, while the sum is 52.

The spelling of 21155705705662 in words is "twenty-one trillion, one hundred fifty-five billion, seven hundred five million, seven hundred five thousand, six hundred sixty-two".