21521001413 has 8 divisors (see below), whose sum is σ = 22269888480. Its totient is φ = 20772566640.

The previous prime is 21521001391. The next prime is 21521001421. The reversal of 21521001413 is 31410012512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21521001413 - 2¹² = 21520997317 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21521001433) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14795 + ... + 207992.

It is an arithmetic number, because the mean of its divisors is an integer number (2783736060).

Almost surely, 2^21521001413 is an apocalyptic number.

It is an amenable number.

21521001413 is a deficient number, since it is larger than the sum of its proper divisors (748887067).

21521001413 is a wasteful number, since it uses less digits than its factorization.

21521001413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226147.

The product of its (nonzero) digits is 240, while the sum is 20.

Adding to 21521001413 its reverse (31410012512), we get a palindrome (52931013925).

The spelling of 21521001413 in words is "twenty-one billion, five hundred twenty-one million, one thousand, four hundred thirteen".