21392126820 has 36 divisors (see below), whose sum is σ = 64889451900. Its totient is φ = 5704567104.

The previous prime is 21392126801. The next prime is 21392126837. The reversal of 21392126820 is 2862129312.

It is a happy number.

21392126820 is a `hidden beast` number, since 2 + 1 + 392 + 1 + 268 + 2 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 8108642304 + 13283484516 = 90048^2 + 115254^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 59422395 + ... + 59422754.

It is an arithmetic number, because the mean of its divisors is an integer number (1802484775).

Almost surely, 2^21392126820 is an apocalyptic number.

21392126820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21392126820 is an abundant number, since it is smaller than the sum of its proper divisors (43497325080).

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

21392126820 is a wasteful number, since it uses less digits than its factorization.

21392126820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118845164 (or 118845159 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The spelling of 21392126820 in words is "twenty-one billion, three hundred ninety-two million, one hundred twenty-six thousand, eight hundred twenty".