21212630521 has 4 divisors (see below), whose sum is σ = 21227052544. Its totient is φ = 21198208500.

The previous prime is 21212630519. The next prime is 21212630531. The reversal of 21212630521 is 12503621212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21212630521 - 2¹ = 21212630519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21212630531) 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, 7208805 + ... + 7211746.

It is an arithmetic number, because the mean of its divisors is an integer number (5306763136).

Almost surely, 2^21212630521 is an apocalyptic number.

It is an amenable number.

21212630521 is a deficient number, since it is larger than the sum of its proper divisors (14422023).

21212630521 is a wasteful number, since it uses less digits than its factorization.

21212630521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14422022.

The product of its (nonzero) digits is 1440, while the sum is 25.

The spelling of 21212630521 in words is "twenty-one billion, two hundred twelve million, six hundred thirty thousand, five hundred twenty-one".