21155435402 has 4 divisors (see below), whose sum is σ = 31733153106. Its totient is φ = 10577717700.

The previous prime is 21155435393. The next prime is 21155435419. The reversal of 21155435402 is 20453455112.

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., 11217139921 + 9938295481 = 105911^2 + 99691^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5288858849 + ... + 5288858852.

Almost surely, 2^21155435402 is an apocalyptic number.

21155435402 is a deficient number, since it is larger than the sum of its proper divisors (10577717704).

21155435402 is a wasteful number, since it uses less digits than its factorization.

21155435402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10577717703.

The product of its (nonzero) digits is 24000, while the sum is 32.

The spelling of 21155435402 in words is "twenty-one billion, one hundred fifty-five million, four hundred thirty-five thousand, four hundred two".