21135237816442 has 4 divisors (see below), whose sum is σ = 31702856724666. Its totient is φ = 10567618908220.

The previous prime is 21135237816421. The next prime is 21135237816479. The reversal of 21135237816442 is 24461873253112.

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., 20369597066361 + 765640750081 = 4513269^2 + 875009^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5283809454109 + ... + 5283809454112.

Almost surely, 2^{21135237816442} is an apocalyptic number.

21135237816442 is a deficient number, since it is larger than the sum of its proper divisors (10567618908224).

21135237816442 is a wasteful number, since it uses less digits than its factorization.

21135237816442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10567618908223.

The product of its digits is 1935360, while the sum is 49.

The spelling of 21135237816442 in words is "twenty-one trillion, one hundred thirty-five billion, two hundred thirty-seven million, eight hundred sixteen thousand, four hundred forty-two".