19215007081 has 4 divisors (see below), whose sum is σ = 19215385812. Its totient is φ = 19214628352.

The previous prime is 19215007051. The next prime is 19215007099. The reversal of 19215007081 is 18070051291.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3007425600 + 16207581481 = 54840^2 + 127309^2 .

It is a cyclic number.

It is not a de Polignac number, because 19215007081 - 2²¹ = 19212909929 is a prime.

It is a super-2 number, since 2×19215007081² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19215007051) 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, 98836 + ... + 219541.

It is an arithmetic number, because the mean of its divisors is an integer number (4803846453).

Almost surely, 2^19215007081 is an apocalyptic number.

It is an amenable number.

19215007081 is a deficient number, since it is larger than the sum of its proper divisors (378731).

19215007081 is an equidigital number, since it uses as much as digits as its factorization.

19215007081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 378730.

The product of its (nonzero) digits is 5040, while the sum is 34.

The spelling of 19215007081 in words is "nineteen billion, two hundred fifteen million, seven thousand, eighty-one".