61621256421643 has 4 divisors (see below), whose sum is σ = 61623546946128. Its totient is φ = 61618965897160.

The previous prime is 61621256421611. The next prime is 61621256421649. The reversal of 61621256421643 is 34612465212616.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 61621256421643 - 2⁵ = 61621256421611 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61621256421649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1145221888 + ... + 1145275693.

It is an arithmetic number, because the mean of its divisors is an integer number (15405886736532).

Almost surely, 2^{61621256421643} is an apocalyptic number.

61621256421643 is a deficient number, since it is larger than the sum of its proper divisors (2290524485).

61621256421643 is a wasteful number, since it uses less digits than its factorization.

61621256421643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2290524484.

The product of its digits is 2488320, while the sum is 49.

The spelling of 61621256421643 in words is "sixty-one trillion, six hundred twenty-one billion, two hundred fifty-six million, four hundred twenty-one thousand, six hundred forty-three".