61722720 has 72 divisors (see below), whose sum is σ = 210633696. Its totient is φ = 16459008.

The previous prime is 61722719. The next prime is 61722743. The reversal of 61722720 is 2722716.

61722720 is a `hidden beast` number, since 617 + 2 + 27 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19992 + ... + 22871.

It is an arithmetic number, because the mean of its divisors is an integer number (2925468).

Almost surely, 2^61722720 is an apocalyptic number.

61722720 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

61722720 is an abundant number, since it is smaller than the sum of its proper divisors (148910976).

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

61722720 is a wasteful number, since it uses less digits than its factorization.

61722720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42884 (or 42873 counting only the distinct ones).

The product of its (nonzero) digits is 2352, while the sum is 27.

The square root of 61722720 is about 7856.3808461657. The cubic root of 61722720 is about 395.1982554409.

The spelling of 61722720 in words is "sixty-one million, seven hundred twenty-two thousand, seven hundred twenty".