20925917951 has 4 divisors (see below), whose sum is σ = 20942918304. Its totient is φ = 20908917600.

The previous prime is 20925917939. The next prime is 20925917953. The reversal of 20925917951 is 15971952902.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20925917951 - 2¹⁰ = 20925916927 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20925917951.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20925917953) 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, 8498330 + ... + 8500791.

It is an arithmetic number, because the mean of its divisors is an integer number (5235729576).

Almost surely, 2^20925917951 is an apocalyptic number.

20925917951 is a deficient number, since it is larger than the sum of its proper divisors (17000353).

20925917951 is a wasteful number, since it uses less digits than its factorization.

20925917951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17000352.

The product of its (nonzero) digits is 510300, while the sum is 50.

The spelling of 20925917951 in words is "twenty billion, nine hundred twenty-five million, nine hundred seventeen thousand, nine hundred fifty-one".