21012156026 has 8 divisors (see below), whose sum is σ = 33372247860. Its totient is φ = 9888073408.

The previous prime is 21012156007. The next prime is 21012156029. The reversal of 21012156026 is 62065121012.

It can be written as a sum of positive squares in 2 ways, for example, as 17490327001 + 3521829025 = 132251^2 + 59345^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×21012156026² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21012155986 and 21012156004.

It is not an unprimeable number, because it can be changed into a prime (21012156029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 309002261 + ... + 309002328.

Almost surely, 2^21012156026 is an apocalyptic number.

21012156026 is a deficient number, since it is larger than the sum of its proper divisors (12360091834).

21012156026 is a wasteful number, since it uses less digits than its factorization.

21012156026 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 618004608.

The product of its (nonzero) digits is 1440, while the sum is 26.

Adding to 21012156026 its reverse (62065121012), we get a palindrome (83077277038).

The spelling of 21012156026 in words is "twenty-one billion, twelve million, one hundred fifty-six thousand, twenty-six".