20967535381 has 4 divisors (see below), whose sum is σ = 22580422732. Its totient is φ = 19354648032.

The previous prime is 20967535349. The next prime is 20967535399. The reversal of 20967535381 is 18353576902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18353576902 = 2 ⋅9176788451.

It can be written as a sum of positive squares in 2 ways, for example, as 13080496900 + 7887038481 = 114370^2 + 88809^2 .

It is a cyclic number.

It is not a de Polignac number, because 20967535381 - 2⁵ = 20967535349 is a prime.

It is a super-2 number, since 2×20967535381² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20967535081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 806443656 + ... + 806443681.

It is an arithmetic number, because the mean of its divisors is an integer number (5645105683).

Almost surely, 2^20967535381 is an apocalyptic number.

It is an amenable number.

20967535381 is a deficient number, since it is larger than the sum of its proper divisors (1612887351).

20967535381 is a wasteful number, since it uses less digits than its factorization.

20967535381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1612887350.

The product of its (nonzero) digits is 1360800, while the sum is 49.

The spelling of 20967535381 in words is "twenty billion, nine hundred sixty-seven million, five hundred thirty-five thousand, three hundred eighty-one".