102521021 has 4 divisors (see below), whose sum is σ = 103052412. Its totient is φ = 101989632.

The previous prime is 102520991. The next prime is 102521039. The reversal of 102521021 is 120125201.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 51912025 + 50608996 = 7205^2 + 7114^2 .

It is a cyclic number.

It is not a de Polignac number, because 102521021 - 2²² = 98326717 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 102520987 and 102521005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (102521071) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 265406 + ... + 265791.

It is an arithmetic number, because the mean of its divisors is an integer number (25763103).

Almost surely, 2^102521021 is an apocalyptic number.

It is an amenable number.

102521021 is a deficient number, since it is larger than the sum of its proper divisors (531391).

102521021 is an equidigital number, since it uses as much as digits as its factorization.

102521021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 531390.

The product of its (nonzero) digits is 40, while the sum is 14.

The square root of 102521021 is about 10125.2664656294. The cubic root of 102521021 is about 468.0270715706.

Adding to 102521021 its reverse (120125201), we get a palindrome (222646222).

The spelling of 102521021 in words is "one hundred two million, five hundred twenty-one thousand, twenty-one".