1564340640421 has 4 divisors (see below), whose sum is σ = 1684674535852. Its totient is φ = 1444006744992.

The previous prime is 1564340640371. The next prime is 1564340640427. The reversal of 1564340640421 is 1240460434651.

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 224856156100 + 1339484484321 = 474190^2 + 1157361^2 .

It is a cyclic number.

It is not a de Polignac number, because 1564340640421 - 2⁷ = 1564340640293 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 (1564340640427) 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, 60166947696 + ... + 60166947721.

It is an arithmetic number, because the mean of its divisors is an integer number (421168633963).

Almost surely, 2^{1564340640421} is an apocalyptic number.

It is an amenable number.

1564340640421 is a deficient number, since it is larger than the sum of its proper divisors (120333895431).

1564340640421 is a wasteful number, since it uses less digits than its factorization.

1564340640421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120333895430.

The product of its (nonzero) digits is 276480, while the sum is 40.

The spelling of 1564340640421 in words is "one trillion, five hundred sixty-four billion, three hundred forty million, six hundred forty thousand, four hundred twenty-one".