20257021634 has 8 divisors (see below), whose sum is σ = 30495228348. Its totient is φ = 10091945520.

The previous prime is 20257021559. The next prime is 20257021657. The reversal of 20257021634 is 43612075202.

It can be written as a sum of positive squares in 2 ways, for example, as 16224390625 + 4032631009 = 127375^2 + 63503^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 20257021634.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18281957 + ... + 18283064.

Almost surely, 2^20257021634 is an apocalyptic number.

20257021634 is a deficient number, since it is larger than the sum of its proper divisors (10238206714).

20257021634 is a wasteful number, since it uses less digits than its factorization.

20257021634 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36565300.

The product of its (nonzero) digits is 20160, while the sum is 32.

Adding to 20257021634 its reverse (43612075202), we get a palindrome (63869096836).

The spelling of 20257021634 in words is "twenty billion, two hundred fifty-seven million, twenty-one thousand, six hundred thirty-four".