61721544 has 16 divisors (see below), whose sum is σ = 154303920. Its totient is φ = 20573840.

The previous prime is 61721533. The next prime is 61721549. The reversal of 61721544 is 44512716.

It is not an unprimeable number, because it can be changed into a prime (61721549) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1285842 + ... + 1285889.

It is an arithmetic number, because the mean of its divisors is an integer number (9643995).

Almost surely, 2^61721544 is an apocalyptic number.

It is an amenable number.

61721544 is an abundant number, since it is smaller than the sum of its proper divisors (92582376).

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

61721544 is a wasteful number, since it uses less digits than its factorization.

61721544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2571740 (or 2571736 counting only the distinct ones).

The product of its digits is 6720, while the sum is 30.

The square root of 61721544 is about 7856.3060021870. The cubic root of 61721544 is about 395.1957455273.

The spelling of 61721544 in words is "sixty-one million, seven hundred twenty-one thousand, five hundred forty-four".