721101620 has 24 divisors (see below), whose sum is σ = 1529310888. Its totient is φ = 285584000.

The previous prime is 721101613. The next prime is 721101649. The reversal of 721101620 is 26101127.

It can be written as a sum of positive squares in 4 ways, for example, as 194490916 + 526610704 = 13946^2 + 22948^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 721101592 and 721101601.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 176471 + ... + 180510.

It is an arithmetic number, because the mean of its divisors is an integer number (63721287).

Almost surely, 2^721101620 is an apocalyptic number.

It is an amenable number.

721101620 is an abundant number, since it is smaller than the sum of its proper divisors (808209268).

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

721101620 is a wasteful number, since it uses less digits than its factorization.

721101620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 357091 (or 357089 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 20.

The square root of 721101620 is about 26853.3353608076. The cubic root of 721101620 is about 896.7378279613.

Adding to 721101620 its reverse (26101127), we get a palindrome (747202747).

The spelling of 721101620 in words is "seven hundred twenty-one million, one hundred one thousand, six hundred twenty".