21315708001 has 9 divisors (see below), whose sum is σ = 24797012499. Its totient is φ = 18269730864.

The previous prime is 21315707921. The next prime is 21315708053. The reversal of 21315708001 is 10080751312.

The square root of 21315708001 is 145999.

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

It can be written as a sum of positive squares in only one way, i.e., 20823933025 + 491774976 = 144305^2 + 22176^2 .

It is not a de Polignac number, because 21315708001 - 2¹³ = 21315699809 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21315708061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1011565 + ... + 1032421.

It is an arithmetic number, because the mean of its divisors is an integer number (2755223611).

Almost surely, 2^21315708001 is an apocalyptic number.

21315708001 is the 145999-th square number.

21315708001 is the 73000-th centered octagonal number.

It is an amenable number.

21315708001 is a deficient number, since it is larger than the sum of its proper divisors (3481304498).

21315708001 is an frugal number, since it uses more digits than its factorization.

21315708001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41728 (or 20864 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 28.

It can be divided in two parts, 21315 and 708001, that added together give a square (729316 = 854²).

The spelling of 21315708001 in words is "twenty-one billion, three hundred fifteen million, seven hundred eight thousand, one".