21261406403061 has 48 divisors (see below), whose sum is σ = 33941584435200. Its totient is φ = 12717997608960.

The previous prime is 21261406403023. The next prime is 21261406403071. The reversal of 21261406403061 is 16030460416212.

21261406403061 is a `hidden beast` number, since 2 + 1 + 2 + 6 + 1 + 4 + 0 + 640 + 3 + 0 + 6 + 1 = 666.

It is not a de Polignac number, because 21261406403061 - 2¹⁵ = 21261406370293 is a prime.

It is a super-2 number, since 2×21261406403061² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21261406403071) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1954336 + ... + 6807513.

It is an arithmetic number, because the mean of its divisors is an integer number (707116342400).

Almost surely, 2^{21261406403061} is an apocalyptic number.

It is an amenable number.

21261406403061 is a deficient number, since it is larger than the sum of its proper divisors (12680178032139).

21261406403061 is a wasteful number, since it uses less digits than its factorization.

21261406403061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8762186 (or 8762183 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

Adding to 21261406403061 its reverse (16030460416212), we get a palindrome (37291866819273).

The spelling of 21261406403061 in words is "twenty-one trillion, two hundred sixty-one billion, four hundred six million, four hundred three thousand, sixty-one".