42990400561 has 2 divisors, whose sum is σ = 42990400562. Its totient is φ = 42990400560.

The previous prime is 42990400543. The next prime is 42990400639. The reversal of 42990400561 is 16500409924.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 41144065600 + 1846334961 = 202840^2 + 42969^2 .

It is a cyclic number.

It is not a de Polignac number, because 42990400561 - 2³¹ = 40842916913 is a prime.

It is a super-2 number, since 2×42990400561² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (42990400961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21495200280 + 21495200281.

It is an arithmetic number, because the mean of its divisors is an integer number (21495200281).

Almost surely, 2^42990400561 is an apocalyptic number.

It is an amenable number.

42990400561 is a deficient number, since it is larger than the sum of its proper divisors (1).

42990400561 is an equidigital number, since it uses as much as digits as its factorization.

42990400561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 77760, while the sum is 40.

The spelling of 42990400561 in words is "forty-two billion, nine hundred ninety million, four hundred thousand, five hundred sixty-one".