21011550061 has 8 divisors (see below), whose sum is σ = 23014680120. Its totient is φ = 19093659648.

The previous prime is 21011550037. The next prime is 21011550097. The reversal of 21011550061 is 16005511012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 11554960036 + 9456590025 = 107494^2 + 97245^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21011550061 - 2¹¹ = 21011548013 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 (21011550011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21309396 + ... + 21310381.

It is an arithmetic number, because the mean of its divisors is an integer number (2876835015).

Almost surely, 2^21011550061 is an apocalyptic number.

It is an amenable number.

21011550061 is a deficient number, since it is larger than the sum of its proper divisors (2003130059).

21011550061 is a wasteful number, since it uses less digits than its factorization.

21011550061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42619823.

The product of its (nonzero) digits is 300, while the sum is 22.

The spelling of 21011550061 in words is "twenty-one billion, eleven million, five hundred fifty thousand, sixty-one".