19811902 has 16 divisors (see below), whose sum is σ = 34327152. Its totient is φ = 8475520.

The previous prime is 19811867. The next prime is 19811903. The reversal of 19811902 is 20911891.

It is a super-2 number, since 2×19811902² = 785022921715208, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19811903) 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, 26113 + ... + 26860.

It is an arithmetic number, because the mean of its divisors is an integer number (2145447).

Almost surely, 2^19811902 is an apocalyptic number.

19811902 is a deficient number, since it is larger than the sum of its proper divisors (14515250).

19811902 is a wasteful number, since it uses less digits than its factorization.

19811902 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53003.

The product of its (nonzero) digits is 1296, while the sum is 31.

The square root of 19811902 is about 4451.0562791320. The cubic root of 19811902 is about 270.5881190240.

It can be divided in two parts, 1981 and 1902, that added together give a palindrome (3883).

The spelling of 19811902 in words is "nineteen million, eight hundred eleven thousand, nine hundred two".