21434627201721 has 4 divisors (see below), whose sum is σ = 28579502935632. Its totient is φ = 14289751467812.

The previous prime is 21434627201717. The next prime is 21434627201821. The reversal of 21434627201721 is 12710272643412.

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 21434627201721 - 2² = 21434627201717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21434627201821) 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, 3572437866951 + ... + 3572437866956.

It is an arithmetic number, because the mean of its divisors is an integer number (7144875733908).

Almost surely, 2^{21434627201721} is an apocalyptic number.

It is an amenable number.

21434627201721 is a deficient number, since it is larger than the sum of its proper divisors (7144875733911).

21434627201721 is an equidigital number, since it uses as much as digits as its factorization.

21434627201721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7144875733910.

The product of its (nonzero) digits is 225792, while the sum is 42.

The spelling of 21434627201721 in words is "twenty-one trillion, four hundred thirty-four billion, six hundred twenty-seven million, two hundred one thousand, seven hundred twenty-one".