402012121421 has 4 divisors (see below), whose sum is σ = 404710189500. Its totient is φ = 399314053344.

The previous prime is 402012121307. The next prime is 402012121487. The reversal of 402012121421 is 124121210204.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 175007518921 + 227004602500 = 418339^2 + 476450^2 .

It is a cyclic number.

It is not a de Polignac number, because 402012121421 - 2¹⁴ = 402012105037 is a prime.

It is a super-2 number, since 2×402012121421² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 402012121393 and 402012121402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (402012021421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1349033816 + ... + 1349034113.

It is an arithmetic number, because the mean of its divisors is an integer number (101177547375).

Almost surely, 2^402012121421 is an apocalyptic number.

It is an amenable number.

402012121421 is a deficient number, since it is larger than the sum of its proper divisors (2698068079).

402012121421 is a wasteful number, since it uses less digits than its factorization.

402012121421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2698068078.

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 402012121421 its reverse (124121210204), we get a palindrome (526133331625).

The spelling of 402012121421 in words is "four hundred two billion, twelve million, one hundred twenty-one thousand, four hundred twenty-one".