64491720 has 64 divisors (see below), whose sum is σ = 196776000. Its totient is φ = 16904448.

The previous prime is 64491683. The next prime is 64491751. The reversal of 64491720 is 2719446.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2526 + ... + 11634.

It is an arithmetic number, because the mean of its divisors is an integer number (3074625).

Almost surely, 2^64491720 is an apocalyptic number.

64491720 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 64491720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (98388000).

64491720 is an abundant number, since it is smaller than the sum of its proper divisors (132284280).

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

64491720 is a wasteful number, since it uses less digits than its factorization.

64491720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9182 (or 9178 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 64491720 is about 8030.6736952761. The cubic root of 64491720 is about 401.0218042343.

The spelling of 64491720 in words is "sixty-four million, four hundred ninety-one thousand, seven hundred twenty".