21860279401 has 4 divisors (see below), whose sum is σ = 21860581204. Its totient is φ = 21859977600.

The previous prime is 21860279387. The next prime is 21860279407. The reversal of 21860279401 is 10497206812.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 177422400 + 21682857001 = 13320^2 + 147251^2 .

It is a 3-Lehmer number, since φ(21860279401) divides (21860279401-1)³.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21860279401 is a prime.

It is a deceptive number, since it divides R_21860279400.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21860279407) 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, 30181 + ... + 211261.

It is an arithmetic number, because the mean of its divisors is an integer number (5465145301).

It is a Poulet number, since it divides 2^21860279400-1.

Almost surely, 2^21860279401 is an apocalyptic number.

21860279401 is the 120721-st pentagonal number.

It is an amenable number.

21860279401 is a deficient number, since it is larger than the sum of its proper divisors (301803).

21860279401 is a wasteful number, since it uses less digits than its factorization.

21860279401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 301802.

The product of its (nonzero) digits is 48384, while the sum is 40.

The spelling of 21860279401 in words is "twenty-one billion, eight hundred sixty million, two hundred seventy-nine thousand, four hundred one".