61421721680 has 80 divisors (see below), whose sum is σ = 156833712000. Its totient is φ = 22185223680.

The previous prime is 61421721671. The next prime is 61421721733. The reversal of 61421721680 is 8612712416.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 103100 + ... + 365339.

It is an arithmetic number, because the mean of its divisors is an integer number (1960421400).

Almost surely, 2^61421721680 is an apocalyptic number.

It is an amenable number.

61421721680 is an abundant number, since it is smaller than the sum of its proper divisors (95411990320).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61421721680 is a wasteful number, since it uses less digits than its factorization.

61421721680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 468612 (or 468606 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 38.

The spelling of 61421721680 in words is "sixty-one billion, four hundred twenty-one million, seven hundred twenty-one thousand, six hundred eighty".