61641554421 has 4 divisors (see below), whose sum is σ = 82188739232. Its totient is φ = 41094369612.

The previous prime is 61641554419. The next prime is 61641554459. The reversal of 61641554421 is 12445514616.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 61641554421 - 2¹ = 61641554419 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 61641554421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61641554461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10273592401 + ... + 10273592406.

It is an arithmetic number, because the mean of its divisors is an integer number (20547184808).

Almost surely, 2^61641554421 is an apocalyptic number.

It is an amenable number.

61641554421 is a deficient number, since it is larger than the sum of its proper divisors (20547184811).

61641554421 is a wasteful number, since it uses less digits than its factorization.

61641554421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20547184810.

The product of its digits is 115200, while the sum is 39.

The spelling of 61641554421 in words is "sixty-one billion, six hundred forty-one million, five hundred fifty-four thousand, four hundred twenty-one".