21719654389225 has 27 divisors (see below), whose sum is σ = 29163862221573. Its totient is φ = 16038905694240.

The previous prime is 21719654389211. The next prime is 21719654389229. The reversal of 21719654389225 is 52298345691712.

The square root of 21719654389225 is 4660435.

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 5598273048489 + 16121381340736 = 2366067^2 + 4015144^2 .

It is not a de Polignac number, because 21719654389225 - 2⁵ = 21719654389193 is a prime.

It is a super-2 number, since 2×21719654389225² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21719654389229) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 302892426 + ... + 302964124.

Almost surely, 2^{21719654389225} is an apocalyptic number.

21719654389225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21719654389225 is the 4660435-th square number.

21719654389225 is the 2330218-th centered octagonal number.

It is an amenable number.

21719654389225 is a deficient number, since it is larger than the sum of its proper divisors (7444207832348).

21719654389225 is an frugal number, since it uses more digits than its factorization.

21719654389225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143434 (or 71717 counting only the distinct ones).

The product of its digits is 65318400, while the sum is 64.

The spelling of 21719654389225 in words is "twenty-one trillion, seven hundred nineteen billion, six hundred fifty-four million, three hundred eighty-nine thousand, two hundred twenty-five".