21371990310225 has 135 divisors (see below), whose sum is σ = 41789301031467. Its totient is φ = 10796482185120.

The previous prime is 21371990310199. The next prime is 21371990310241. The reversal of 21371990310225 is 52201309917312.

The square root of 21371990310225 is 4622985.

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

21371990310225 is a `hidden beast` number, since 2 + 13 + 7 + 19 + 90 + 310 + 225 = 666.

It can be written as a sum of positive squares in only one way, i.e., 7693916511681 + 13678073798544 = 2773791^2 + 3698388^2 .

It is a tau number, because it is divible by the number of its divisors (135).

It is not a de Polignac number, because 21371990310225 - 2⁵ = 21371990310193 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 3952649472 + ... + 3952654878.

Almost surely, 2^{21371990310225} is an apocalyptic number.

21371990310225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21371990310225 is the 4622985-th square number.

21371990310225 is the 2311493-rd centered octagonal number.

It is an amenable number.

21371990310225 is a deficient number, since it is larger than the sum of its proper divisors (20417310721242).

21371990310225 is an frugal number, since it uses more digits than its factorization.

21371990310225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10874 (or 5434 counting only the distinct ones).

The product of its (nonzero) digits is 204120, while the sum is 45.

The spelling of 21371990310225 in words is "twenty-one trillion, three hundred seventy-one billion, nine hundred ninety million, three hundred ten thousand, two hundred twenty-five".