1721420100 has 135 divisors (see below), whose sum is σ = 5592294631. Its totient is φ = 458049600.

The previous prime is 1721420093. The next prime is 1721420149. The reversal of 1721420100 is 10241271.

The square root of 1721420100 is 41490.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 175986756 + 1545433344 = 13266^2 + 39312^2 .

It is a tau number, because it is divible by the number of its divisors (135).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 3733870 + ... + 3734330.

Almost surely, 2^1721420100 is an apocalyptic number.

1721420100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1721420100 is the 41490-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1721420100

1721420100 is an abundant number, since it is smaller than the sum of its proper divisors (3870874531).

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

1721420100 is an equidigital number, since it uses as much as digits as its factorization.

1721420100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 948 (or 471 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The cubic root of 1721420100 is about 1198.4749376417.

Adding to 1721420100 its reverse (10241271), we get a palindrome (1731661371).

It can be divided in two parts, 1721 and 420100, that added together give a triangular number (421821 = T₉₁₈).

The spelling of 1721420100 in words is "one billion, seven hundred twenty-one million, four hundred twenty thousand, one hundred".