1721223551 has 2 divisors, whose sum is σ = 1721223552. Its totient is φ = 1721223550.

The previous prime is 1721223529. The next prime is 1721223593. The reversal of 1721223551 is 1553221271.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1721223551 - 2¹⁰ = 1721222527 is a prime.

It is a super-2 number, since 2×1721223551² = 5925221025034099202, which contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1721223521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860611775 + 860611776.

It is an arithmetic number, because the mean of its divisors is an integer number (860611776).

Almost surely, 2^1721223551 is an apocalyptic number.

1721223551 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721223551 is an equidigital number, since it uses as much as digits as its factorization.

1721223551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4200, while the sum is 29.

The square root of 1721223551 is about 41487.6313013891. The cubic root of 1721223551 is about 1198.4293225870.

The spelling of 1721223551 in words is "one billion, seven hundred twenty-one million, two hundred twenty-three thousand, five hundred fifty-one".