21565070101 has 4 divisors (see below), whose sum is σ = 21565406304. Its totient is φ = 21564733900.

The previous prime is 21565070099. The next prime is 21565070123. The reversal of 21565070101 is 10107056512.

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 21565070101 - 2¹ = 21565070099 is a prime.

It is a super-4 number, since 4×21565070101⁴ (a number of 42 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21565070101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21565070171) 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, 38665 + ... + 211246.

It is an arithmetic number, because the mean of its divisors is an integer number (5391351576).

Almost surely, 2^21565070101 is an apocalyptic number.

It is an amenable number.

21565070101 is a deficient number, since it is larger than the sum of its proper divisors (336203).

21565070101 is an equidigital number, since it uses as much as digits as its factorization.

21565070101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336202.

The product of its (nonzero) digits is 2100, while the sum is 28.

The spelling of 21565070101 in words is "twenty-one billion, five hundred sixty-five million, seventy thousand, one hundred one".