61989840 has 160 divisors (see below), whose sum is σ = 233020800. Its totient is φ = 15022080.

The previous prime is 61989839. The next prime is 61989877. The reversal of 61989840 is 4898916.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 22456 + ... + 25064.

It is an arithmetic number, because the mean of its divisors is an integer number (1456380).

Almost surely, 2^61989840 is an apocalyptic number.

61989840 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61989840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116510400).

61989840 is an abundant number, since it is smaller than the sum of its proper divisors (171030960).

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

61989840 is a wasteful number, since it uses less digits than its factorization.

61989840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2642 (or 2630 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 45.

The square root of 61989840 is about 7873.3626869337. The cubic root of 61989840 is about 395.7675403361.

The spelling of 61989840 in words is "sixty-one million, nine hundred eighty-nine thousand, eight hundred forty".