21690514729 has 9 divisors (see below), whose sum is σ = 23489435493. Its totient is φ = 20020246272.

The previous prime is 21690514721. The next prime is 21690514751. The reversal of 21690514729 is 92741509612.

The square root of 21690514729 is 147277.

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 5750947225 + 15939567504 = 75835^2 + 126252^2 .

It is not a de Polignac number, because 21690514729 - 2³ = 21690514721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21690514721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1908937 + ... + 1920265.

It is an arithmetic number, because the mean of its divisors is an integer number (2609937277).

Almost surely, 2^21690514729 is an apocalyptic number.

21690514729 is the 147277-th square number.

21690514729 is the 73639-th centered octagonal number.

It is an amenable number.

21690514729 is a deficient number, since it is larger than the sum of its proper divisors (1798920764).

21690514729 is an frugal number, since it uses more digits than its factorization.

21690514729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22684 (or 11342 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 46.

The spelling of 21690514729 in words is "twenty-one billion, six hundred ninety million, five hundred fourteen thousand, seven hundred twenty-nine".