21355426988 has 24 divisors (see below), whose sum is σ = 42767768064. Its totient is φ = 9140130000.

The previous prime is 21355426949. The next prime is 21355426997. The reversal of 21355426988 is 88962455312.

It is a happy number.

It is a super-5 number, since 5×21355426988⁵ (a number of 53 digits) contains 55555 as substring.

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 7 ways as a sum of consecutive naturals, for example, 486758 + ... + 528813.

It is an arithmetic number, because the mean of its divisors is an integer number (1781990336).

Almost surely, 2^21355426988 is an apocalyptic number.

21355426988 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21355426988 is an abundant number, since it is smaller than the sum of its proper divisors (21412341076).

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

21355426988 is a wasteful number, since it uses less digits than its factorization.

21355426988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1016333 (or 1016331 counting only the distinct ones).

The product of its digits is 4147200, while the sum is 53.

The spelling of 21355426988 in words is "twenty-one billion, three hundred fifty-five million, four hundred twenty-six thousand, nine hundred eighty-eight".