1561231451 has 4 divisors (see below), whose sum is σ = 1681326192. Its totient is φ = 1441136712.

The previous prime is 1561231433. The next prime is 1561231489. The reversal of 1561231451 is 1541321651.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1561231451 - 2²⁶ = 1494122587 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1561231351) 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, 60047351 + ... + 60047376.

It is an arithmetic number, because the mean of its divisors is an integer number (420331548).

Almost surely, 2^1561231451 is an apocalyptic number.

1561231451 is a deficient number, since it is larger than the sum of its proper divisors (120094741).

1561231451 is a wasteful number, since it uses less digits than its factorization.

1561231451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120094740.

The product of its digits is 3600, while the sum is 29.

The square root of 1561231451 is about 39512.4214773026. The cubic root of 1561231451 is about 1160.0830922940.

The spelling of 1561231451 in words is "one billion, five hundred sixty-one million, two hundred thirty-one thousand, four hundred fifty-one".