61801084021 has 8 divisors (see below), whose sum is σ = 62479680984. Its totient is φ = 61123795200.

The previous prime is 61801083991. The next prime is 61801084031. The reversal of 61801084021 is 12048010816.

61801084021 = 175785² + 175786².

It can be written as a sum of positive squares in 4 ways, for example, as 30900717796 + 30900366225 = 175786^2 + 175785^2 .

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 61801084021 - 2¹¹ = 61801081973 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 (61801084031) 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, 231880 + ... + 421153.

It is an arithmetic number, because the mean of its divisors is an integer number (7809960123).

Almost surely, 2^61801084021 is an apocalyptic number.

61801084021 is the 175786-th centered square number.

It is an amenable number.

61801084021 is a deficient number, since it is larger than the sum of its proper divisors (678596963).

61801084021 is a wasteful number, since it uses less digits than its factorization.

61801084021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 654071.

The product of its (nonzero) digits is 3072, while the sum is 31.

Adding to 61801084021 its reverse (12048010816), we get a palindrome (73849094837).

The spelling of 61801084021 in words is "sixty-one billion, eight hundred one million, eighty-four thousand, twenty-one".