21121404402 has 32 divisors (see below), whose sum is σ = 48544239744. Its totient is φ = 6001344000.

The previous prime is 21121404373. The next prime is 21121404419. The reversal of 21121404402 is 20440412112.

It is a super-2 number, since 2×21121404402² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1381599 + ... + 1396802.

It is an arithmetic number, because the mean of its divisors is an integer number (1517007492).

Almost surely, 2^21121404402 is an apocalyptic number.

21121404402 is an abundant number, since it is smaller than the sum of its proper divisors (27422835342).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21121404402 is a wasteful number, since it uses less digits than its factorization.

21121404402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2778594.

The product of its (nonzero) digits is 512, while the sum is 21.

Adding to 21121404402 its reverse (20440412112), we get a palindrome (41561816514).

The spelling of 21121404402 in words is "twenty-one billion, one hundred twenty-one million, four hundred four thousand, four hundred two".