21423537820728 has 24 divisors (see below), whose sum is σ = 58022081598000. Its totient is φ = 7141179273552.

The previous prime is 21423537820681. The next prime is 21423537820771. The reversal of 21423537820728 is 82702873532412.

It is a happy number.

21423537820728 is a `hidden beast` number, since 2 + 1 + 4 + 2 + 3 + 537 + 82 + 0 + 7 + 28 = 666.

It is a tau number, because it is divible by the number of its divisors (24).

It is a super-3 number, since 3×21423537820728³ (a number of 41 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 148774568128 + ... + 148774568271.

It is an arithmetic number, because the mean of its divisors is an integer number (2417586733250).

Almost surely, 2^{21423537820728} is an apocalyptic number.

It is an amenable number.

21423537820728 is an abundant number, since it is smaller than the sum of its proper divisors (36598543777272).

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

21423537820728 is a wasteful number, since it uses less digits than its factorization.

21423537820728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 297549136411 (or 297549136404 counting only the distinct ones).

The product of its (nonzero) digits is 9031680, while the sum is 54.

The spelling of 21423537820728 in words is "twenty-one trillion, four hundred twenty-three billion, five hundred thirty-seven million, eight hundred twenty thousand, seven hundred twenty-eight".