21601703431638 has 24 divisors (see below), whose sum is σ = 51058571747976. Its totient is φ = 6545970736800.

The previous prime is 21601703431603. The next prime is 21601703431639. The reversal of 21601703431638 is 83613430710612.

21601703431638 is a `hidden beast` number, since 2 + 1 + 6 + 0 + 1 + 7 + 0 + 3 + 4 + 3 + 1 + 638 = 666.

It is a super-2 number, since 2×21601703431638² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21601703431593 and 21601703431602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21601703431639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 54549755943 + ... + 54549756338.

It is an arithmetic number, because the mean of its divisors is an integer number (2127440489499).

Almost surely, 2^{21601703431638} is an apocalyptic number.

21601703431638 is an abundant number, since it is smaller than the sum of its proper divisors (29456868316338).

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

21601703431638 is a wasteful number, since it uses less digits than its factorization.

21601703431638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109099512300 (or 109099512297 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 45.

The spelling of 21601703431638 in words is "twenty-one trillion, six hundred one billion, seven hundred three million, four hundred thirty-one thousand, six hundred thirty-eight".