402169681 has 2 divisors, whose sum is σ = 402169682. Its totient is φ = 402169680.

The previous prime is 402169667. The next prime is 402169699. The reversal of 402169681 is 186961204.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 259725456 + 142444225 = 16116^2 + 11935^2 .

It is a cyclic number.

It is not a de Polignac number, because 402169681 - 2¹³ = 402161489 is a prime.

It is a super-2 number, since 2×402169681² = 323480904631283522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 402169681.

It is not a weakly prime, because it can be changed into another prime (402169381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201084840 + 201084841.

It is an arithmetic number, because the mean of its divisors is an integer number (201084841).

Almost surely, 2^402169681 is an apocalyptic number.

It is an amenable number.

402169681 is a deficient number, since it is larger than the sum of its proper divisors (1).

402169681 is an equidigital number, since it uses as much as digits as its factorization.

402169681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 402169681 is about 20054.1686688828. The cubic root of 402169681 is about 738.1360937853.

The spelling of 402169681 in words is "four hundred two million, one hundred sixty-nine thousand, six hundred eighty-one".