61821920 has 48 divisors (see below), whose sum is σ = 149179968. Its totient is φ = 24199680.

The previous prime is 61821889. The next prime is 61821923. The reversal of 61821920 is 2912816.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61821923) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3410 + ... + 11630.

It is an arithmetic number, because the mean of its divisors is an integer number (3107916).

Almost surely, 2^61821920 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61821920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (74589984).

61821920 is an abundant number, since it is smaller than the sum of its proper divisors (87358048).

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

61821920 is a wasteful number, since it uses less digits than its factorization.

61821920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8283 (or 8275 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 61821920 is about 7862.6916510823. The cubic root of 61821920 is about 395.4098613840.

The spelling of 61821920 in words is "sixty-one million, eight hundred twenty-one thousand, nine hundred twenty".