21431524801954 has 4 divisors (see below), whose sum is σ = 32147287202934. Its totient is φ = 10715762400976.

The previous prime is 21431524801937. The next prime is 21431524801997. The reversal of 21431524801954 is 45910842513412.

It is a happy number.

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

It can be written as a sum of positive squares in only one way, i.e., 15055773551329 + 6375751250625 = 3880177^2 + 2525025^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21431524801898 and 21431524801907.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5357881200487 + ... + 5357881200490.

Almost surely, 2^{21431524801954} is an apocalyptic number.

21431524801954 is a deficient number, since it is larger than the sum of its proper divisors (10715762400980).

21431524801954 is a wasteful number, since it uses less digits than its factorization.

21431524801954 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10715762400979.

The product of its (nonzero) digits is 1382400, while the sum is 49.

The spelling of 21431524801954 in words is "twenty-one trillion, four hundred thirty-one billion, five hundred twenty-four million, eight hundred one thousand, nine hundred fifty-four".