21738410781 has 8 divisors (see below), whose sum is σ = 29691488064. Its totient is φ = 14138803680.

The previous prime is 21738410773. The next prime is 21738410783. The reversal of 21738410781 is 18701483712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21738410781 - 2³ = 21738410773 is a prime.

It is a super-2 number, since 2×21738410781² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21738410783) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 88367401 + ... + 88367646.

It is an arithmetic number, because the mean of its divisors is an integer number (3711436008).

Almost surely, 2^21738410781 is an apocalyptic number.

It is an amenable number.

21738410781 is a deficient number, since it is larger than the sum of its proper divisors (7953077283).

21738410781 is a wasteful number, since it uses less digits than its factorization.

21738410781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176735091.

The product of its (nonzero) digits is 75264, while the sum is 42.

The spelling of 21738410781 in words is "twenty-one billion, seven hundred thirty-eight million, four hundred ten thousand, seven hundred eighty-one".