20621001565 has 16 divisors (see below), whose sum is σ = 25009145280. Its totient is φ = 16320960000.

The previous prime is 20621001503. The next prime is 20621001589. The reversal of 20621001565 is 56510012602.

It is not a de Polignac number, because 20621001565 - 2⁹ = 20621001053 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1827190 + ... + 1838440.

It is an arithmetic number, because the mean of its divisors is an integer number (1563071580).

Almost surely, 2^20621001565 is an apocalyptic number.

It is an amenable number.

20621001565 is a deficient number, since it is larger than the sum of its proper divisors (4388143715).

20621001565 is a wasteful number, since it uses less digits than its factorization.

20621001565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15132.

The product of its (nonzero) digits is 3600, while the sum is 28.

The spelling of 20621001565 in words is "twenty billion, six hundred twenty-one million, one thousand, five hundred sixty-five".