561400987 has 12 divisors (see below), whose sum is σ = 668988936. Its totient is φ = 469462560.

The previous prime is 561400981. The next prime is 561400993. The reversal of 561400987 is 789004165.

561400987 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (561400981) and next prime (561400993).

It is a de Polignac number, because none of the positive numbers 2^k-561400987 is a prime.

It is not an unprimeable number, because it can be changed into a prime (561400981) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 137713 + ... + 141730.

It is an arithmetic number, because the mean of its divisors is an integer number (55749078).

Almost surely, 2^561400987 is an apocalyptic number.

561400987 is a deficient number, since it is larger than the sum of its proper divisors (107587949).

561400987 is a wasteful number, since it uses less digits than its factorization.

561400987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 279498 (or 279491 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 40.

The square root of 561400987 is about 23693.9018947914. The cubic root of 561400987 is about 824.9438526833.

The spelling of 561400987 in words is "five hundred sixty-one million, four hundred thousand, nine hundred eighty-seven".