402140021 has 4 divisors (see below), whose sum is σ = 402629472. Its totient is φ = 401650572.

The previous prime is 402140017. The next prime is 402140033. The reversal of 402140021 is 120041204.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 402140021 - 2² = 402140017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 402139978 and 402140005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (402140051) 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, 243491 + ... + 245136.

It is an arithmetic number, because the mean of its divisors is an integer number (100657368).

Almost surely, 2^402140021 is an apocalyptic number.

It is an amenable number.

402140021 is a deficient number, since it is larger than the sum of its proper divisors (489451).

402140021 is an equidigital number, since it uses as much as digits as its factorization.

402140021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 489450.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 402140021 is about 20053.4291581265. The cubic root of 402140021 is about 738.1179475021.

Adding to 402140021 its reverse (120041204), we get a palindrome (522181225).

The spelling of 402140021 in words is "four hundred two million, one hundred forty thousand, twenty-one".