21130501642 has 4 divisors (see below), whose sum is σ = 31695752466. Its totient is φ = 10565250820.

The previous prime is 21130501633. The next prime is 21130501661. The reversal of 21130501642 is 24610503112.

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., 20394410481 + 736091161 = 142809^2 + 27131^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5282625409 + ... + 5282625412.

Almost surely, 2^21130501642 is an apocalyptic number.

21130501642 is a deficient number, since it is larger than the sum of its proper divisors (10565250824).

21130501642 is a wasteful number, since it uses less digits than its factorization.

21130501642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10565250823.

The product of its (nonzero) digits is 1440, while the sum is 25.

The spelling of 21130501642 in words is "twenty-one billion, one hundred thirty million, five hundred one thousand, six hundred forty-two".