21011354356 has 24 divisors (see below), whose sum is σ = 37412270280. Its totient is φ = 10323205632.

The previous prime is 21011354341. The next prime is 21011354387. The reversal of 21011354356 is 65345311012.

It can be written as a sum of positive squares in 4 ways, for example, as 1720922256 + 19290432100 = 41484^2 + 138890^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55201 + ... + 212296.

It is an arithmetic number, because the mean of its divisors is an integer number (1558844595).

Almost surely, 2^21011354356 is an apocalyptic number.

It is an amenable number.

21011354356 is a deficient number, since it is larger than the sum of its proper divisors (16400915924).

21011354356 is a wasteful number, since it uses less digits than its factorization.

21011354356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 267843 (or 267841 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 31.

Adding to 21011354356 its reverse (65345311012), we get a palindrome (86356665368).

The spelling of 21011354356 in words is "twenty-one billion, eleven million, three hundred fifty-four thousand, three hundred fifty-six".