21510401005 has 8 divisors (see below), whose sum is σ = 25836816024. Its totient is φ = 17192097600.

The previous prime is 21510400999. The next prime is 21510401009. The reversal of 21510401005 is 50010401512.

It can be written as a sum of positive squares in 4 ways, for example, as 9672525801 + 11837875204 = 98349^2 + 108802^2 .

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

It is not a de Polignac number, because 21510401005 - 2³ = 21510400997 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 (21510401009) 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, 2022066 + ... + 2032675.

It is an arithmetic number, because the mean of its divisors is an integer number (3229602003).

Almost surely, 2^21510401005 is an apocalyptic number.

It is an amenable number.

21510401005 is a deficient number, since it is larger than the sum of its proper divisors (4326415019).

21510401005 is a wasteful number, since it uses less digits than its factorization.

21510401005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4055807.

The product of its (nonzero) digits is 200, while the sum is 19.

Adding to 21510401005 its reverse (50010401512), we get a palindrome (71520802517).

The spelling of 21510401005 in words is "twenty-one billion, five hundred ten million, four hundred one thousand, five".