61505541447421 has 8 divisors (see below), whose sum is σ = 61511582957400. Its totient is φ = 61499500276032.

The previous prime is 61505541447419. The next prime is 61505541447431. The reversal of 61505541447421 is 12474414550516.

It can be written as a sum of positive squares in 4 ways, for example, as 132888682521 + 61372652764900 = 364539^2 + 7834070^2 .

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 61505541447421 - 2¹ = 61505541447419 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 (61505541447431) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 492561231 + ... + 492686083.

It is an arithmetic number, because the mean of its divisors is an integer number (7688947869675).

Almost surely, 2^{61505541447421} is an apocalyptic number.

It is an amenable number.

61505541447421 is a deficient number, since it is larger than the sum of its proper divisors (6041509979).

61505541447421 is a wasteful number, since it uses less digits than its factorization.

61505541447421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169295.

The product of its (nonzero) digits is 2688000, while the sum is 49.

Adding to 61505541447421 its reverse (12474414550516), we get a palindrome (73979955997937).

The spelling of 61505541447421 in words is "sixty-one trillion, five hundred five billion, five hundred forty-one million, four hundred forty-seven thousand, four hundred twenty-one".