21153034103661 has 20 divisors (see below), whose sum is σ = 31605659400700. Its totient is φ = 14099040449856.

The previous prime is 21153034103647. The next prime is 21153034103687. The reversal of 21153034103661 is 16630143035112.

21153034103661 is a `hidden beast` number, since 2 + 1 + 1 + 530 + 34 + 1 + 0 + 36 + 61 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 4275776162025 + 16877257941636 = 2067795^2 + 4108194^2 .

It is not a de Polignac number, because 21153034103661 - 2⁷ = 21153034103533 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21153034103261) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 27228346 + ... + 27994443.

It is an arithmetic number, because the mean of its divisors is an integer number (1580282970035).

Almost surely, 2^{21153034103661} is an apocalyptic number.

It is an amenable number.

21153034103661 is a deficient number, since it is larger than the sum of its proper divisors (10452625297039).

21153034103661 is an equidigital number, since it uses as much as digits as its factorization.

21153034103661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55227530 (or 55227521 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

Adding to 21153034103661 its reverse (16630143035112), we get a palindrome (37783177138773).

The spelling of 21153034103661 in words is "twenty-one trillion, one hundred fifty-three billion, thirty-four million, one hundred three thousand, six hundred sixty-one".