20928363491 has 8 divisors (see below), whose sum is σ = 24406255200. Its totient is φ = 17938596984.

The previous prime is 20928363457. The next prime is 20928363509. The reversal of 20928363491 is 19436382902.

It is not a de Polignac number, because 20928363491 - 2¹⁸ = 20928101347 is a prime.

It is a super-2 number, since 2×20928363491² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20928362491) 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, 30507476 + ... + 30508161.

It is an arithmetic number, because the mean of its divisors is an integer number (3050781900).

Almost surely, 2^20928363491 is an apocalyptic number.

20928363491 is a deficient number, since it is larger than the sum of its proper divisors (3477891709).

20928363491 is an frugal number, since it uses more digits than its factorization.

20928363491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61015658 (or 61015644 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 47.

The spelling of 20928363491 in words is "twenty billion, nine hundred twenty-eight million, three hundred sixty-three thousand, four hundred ninety-one".