20190390856 has 8 divisors (see below), whose sum is σ = 37856982870. Its totient is φ = 10095195424.

The previous prime is 20190390853. The next prime is 20190390859. The reversal of 20190390856 is 65809309102.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20190390853) and next prime (20190390859).

It can be written as a sum of positive squares in only one way, i.e., 19108638756 + 1081752100 = 138234^2 + 32890^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (20190390853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1261899421 + ... + 1261899436.

Almost surely, 2^20190390856 is an apocalyptic number.

It is an amenable number.

20190390856 is a deficient number, since it is larger than the sum of its proper divisors (17666592014).

20190390856 is a wasteful number, since it uses less digits than its factorization.

20190390856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2523798863 (or 2523798859 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 43.

Adding to 20190390856 its reverse (65809309102), we get a palindrome (85999699958).

The spelling of 20190390856 in words is "twenty billion, one hundred ninety million, three hundred ninety thousand, eight hundred fifty-six".