15721781345 has 8 divisors (see below), whose sum is σ = 18889066176. Its totient is φ = 12562139376.

The previous prime is 15721781323. The next prime is 15721781359. The reversal of 15721781345 is 54318712751.

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 15721781345 - 2¹⁶ = 15721715809 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 15721781296 and 15721781305.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1906187 + ... + 1914416.

It is an arithmetic number, because the mean of its divisors is an integer number (2361133272).

Almost surely, 2^15721781345 is an apocalyptic number.

It is an amenable number.

15721781345 is a deficient number, since it is larger than the sum of its proper divisors (3167284831).

15721781345 is an equidigital number, since it uses as much as digits as its factorization.

15721781345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3821431.

The product of its digits is 235200, while the sum is 44.

The spelling of 15721781345 in words is "fifteen billion, seven hundred twenty-one million, seven hundred eighty-one thousand, three hundred forty-five".