1720021461251 has 4 divisors (see below), whose sum is σ = 1810548906600. Its totient is φ = 1629494015904.

The previous prime is 1720021461247. The next prime is 1720021461269. The reversal of 1720021461251 is 1521641200271.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1720021461251 - 2² = 1720021461247 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1720021461281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45263722646 + ... + 45263722683.

It is an arithmetic number, because the mean of its divisors is an integer number (452637226650).

Almost surely, 2^{1720021461251} is an apocalyptic number.

1720021461251 is a deficient number, since it is larger than the sum of its proper divisors (90527445349).

1720021461251 is an equidigital number, since it uses as much as digits as its factorization.

1720021461251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90527445348.

The product of its (nonzero) digits is 6720, while the sum is 32.

The spelling of 1720021461251 in words is "one trillion, seven hundred twenty billion, twenty-one million, four hundred sixty-one thousand, two hundred fifty-one".