21045647415 has 32 divisors (see below), whose sum is σ = 36270440640. Its totient is φ = 10358885376.

The previous prime is 21045647387. The next prime is 21045647417. The reversal of 21045647415 is 51474654012.

It is not a de Polignac number, because 21045647415 - 2¹¹ = 21045645367 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21045647417) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1598881 + ... + 1611989.

It is an arithmetic number, because the mean of its divisors is an integer number (1133451270).

Almost surely, 2^21045647415 is an apocalyptic number.

21045647415 is a deficient number, since it is larger than the sum of its proper divisors (15224793225).

21045647415 is a wasteful number, since it uses less digits than its factorization.

21045647415 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21363.

The product of its (nonzero) digits is 134400, while the sum is 39.

The spelling of 21045647415 in words is "twenty-one billion, forty-five million, six hundred forty-seven thousand, four hundred fifteen".