21541321042 has 8 divisors (see below), whose sum is σ = 33185278476. Its totient is φ = 10479561552.

The previous prime is 21541321037. The next prime is 21541321057. The reversal of 21541321042 is 24012314512.

It can be written as a sum of positive squares in 2 ways, for example, as 17856709641 + 3684611401 = 133629^2 + 60701^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 21541320998 and 21541321016.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 145549393 + ... + 145549540.

Almost surely, 2^21541321042 is an apocalyptic number.

21541321042 is a deficient number, since it is larger than the sum of its proper divisors (11643957434).

21541321042 is a wasteful number, since it uses less digits than its factorization.

21541321042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291098972.

The product of its (nonzero) digits is 1920, while the sum is 25.

Adding to 21541321042 its reverse (24012314512), we get a palindrome (45553635554).

The spelling of 21541321042 in words is "twenty-one billion, five hundred forty-one million, three hundred twenty-one thousand, forty-two".