21195434478 has 16 divisors (see below), whose sum is σ = 42543907920. Its totient is φ = 7039638336.

The previous prime is 21195434473. The next prime is 21195434489. The reversal of 21195434478 is 87443459112.

It is a super-2 number, since 2×21195434478² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21195434473) 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, 6374823 + ... + 6378146.

It is an arithmetic number, because the mean of its divisors is an integer number (2658994245).

Almost surely, 2^21195434478 is an apocalyptic number.

21195434478 is an abundant number, since it is smaller than the sum of its proper divisors (21348473442).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21195434478 is a wasteful number, since it uses less digits than its factorization.

21195434478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12753251.

The product of its digits is 967680, while the sum is 48.

The spelling of 21195434478 in words is "twenty-one billion, one hundred ninety-five million, four hundred thirty-four thousand, four hundred seventy-eight".