21113680642 has 4 divisors (see below), whose sum is σ = 31670520966. Its totient is φ = 10556840320.

The previous prime is 21113680639. The next prime is 21113680657. The reversal of 21113680642 is 24608631112.

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., 18730385881 + 2383294761 = 136859^2 + 48819^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21113680598 and 21113680607.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5278420159 + ... + 5278420162.

Almost surely, 2^21113680642 is an apocalyptic number.

21113680642 is a deficient number, since it is larger than the sum of its proper divisors (10556840324).

21113680642 is a wasteful number, since it uses less digits than its factorization.

21113680642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10556840323.

The product of its (nonzero) digits is 13824, while the sum is 34.

The spelling of 21113680642 in words is "twenty-one billion, one hundred thirteen million, six hundred eighty thousand, six hundred forty-two".