21142286781 has 32 divisors (see below), whose sum is σ = 36279361536. Its totient is φ = 10628712000.

The previous prime is 21142286747. The next prime is 21142286807. The reversal of 21142286781 is 18768224112.

It is not a de Polignac number, because 21142286781 - 2⁶ = 21142286717 is a prime.

It is a super-2 number, since 2×21142286781² (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 (21142286381) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1469050 + ... + 1483371.

It is an arithmetic number, because the mean of its divisors is an integer number (1133730048).

Almost surely, 2^21142286781 is an apocalyptic number.

21142286781 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21142286781 is a deficient number, since it is larger than the sum of its proper divisors (15137074755).

21142286781 is a wasteful number, since it uses less digits than its factorization.

21142286781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2952473.

The product of its digits is 86016, while the sum is 42.

The spelling of 21142286781 in words is "twenty-one billion, one hundred forty-two million, two hundred eighty-six thousand, seven hundred eighty-one".