21215487545 has 8 divisors (see below), whose sum is σ = 29095525824. Its totient is φ = 14547762864.

The previous prime is 21215487463. The next prime is 21215487547. The reversal of 21215487545 is 54578451212.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21215487545 - 2¹⁸ = 21215225401 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21215487496 and 21215487505.

It is not an unprimeable number, because it can be changed into a prime (21215487547) 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, 303078359 + ... + 303078428.

It is an arithmetic number, because the mean of its divisors is an integer number (3636940728).

Almost surely, 2^21215487545 is an apocalyptic number.

It is an amenable number.

21215487545 is a deficient number, since it is larger than the sum of its proper divisors (7880038279).

21215487545 is an equidigital number, since it uses as much as digits as its factorization.

21215487545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 606156799.

The product of its digits is 448000, while the sum is 44.

The spelling of 21215487545 in words is "twenty-one billion, two hundred fifteen million, four hundred eighty-seven thousand, five hundred forty-five".