1561142051 has 16 divisors (see below), whose sum is σ = 1850032128. Its totient is φ = 1289109600.

The previous prime is 1561142041. The next prime is 1561142069. The reversal of 1561142051 is 1502411651.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1561142051 is a prime.

1561142051 is a modest number, since divided by 142051 gives 1561 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 1561142051.

It is not an unprimeable number, because it can be changed into a prime (1561142021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32261 + ... + 64521.

It is an arithmetic number, because the mean of its divisors is an integer number (115627008).

Almost surely, 2^1561142051 is an apocalyptic number.

1561142051 is the 32261-st pentagonal number.

1561142051 is a deficient number, since it is larger than the sum of its proper divisors (288890077).

1561142051 is a wasteful number, since it uses less digits than its factorization.

1561142051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32522.

The product of its (nonzero) digits is 1200, while the sum is 26.

The square root of 1561142051 is about 39511.2901712915. The cubic root of 1561142051 is about 1160.0609487892.

The spelling of 1561142051 in words is "one billion, five hundred sixty-one million, one hundred forty-two thousand, fifty-one".