1653221720 has 16 divisors (see below), whose sum is σ = 3719748960. Its totient is φ = 661288672.

The previous prime is 1653221719. The next prime is 1653221737. The reversal of 1653221720 is 271223561.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20665232 + ... + 20665311.

It is an arithmetic number, because the mean of its divisors is an integer number (232484310).

Almost surely, 2^1653221720 is an apocalyptic number.

1653221720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1653221720 is an abundant number, since it is smaller than the sum of its proper divisors (2066527240).

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

1653221720 is a wasteful number, since it uses less digits than its factorization.

1653221720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41330554 (or 41330550 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 1653221720 is about 40659.8293159231. The cubic root of 1653221720 is about 1182.4343405832.

The spelling of 1653221720 in words is "one billion, six hundred fifty-three million, two hundred twenty-one thousand, seven hundred twenty".