21161554142 has 4 divisors (see below), whose sum is σ = 31742331216. Its totient is φ = 10580777070.

The previous prime is 21161554123. The next prime is 21161554153. The reversal of 21161554142 is 24145516112.

It is a happy number.

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

It is a super-2 number, since 2×21161554142² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21161554099 and 21161554108.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5290388534 + ... + 5290388537.

It is an arithmetic number, because the mean of its divisors is an integer number (7935582804).

Almost surely, 2^21161554142 is an apocalyptic number.

21161554142 is a deficient number, since it is larger than the sum of its proper divisors (10580777074).

21161554142 is a wasteful number, since it uses less digits than its factorization.

21161554142 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10580777073.

The product of its digits is 9600, while the sum is 32.

The spelling of 21161554142 in words is "twenty-one billion, one hundred sixty-one million, five hundred fifty-four thousand, one hundred forty-two".