61011555551 has 4 divisors (see below), whose sum is σ = 61012556472. Its totient is φ = 61010554632.

The previous prime is 61011555529. The next prime is 61011555569. The reversal of 61011555551 is 15555511016.

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 61011555551 - 2⁶ = 61011555487 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61011555581) 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, 402656 + ... + 533061.

It is an arithmetic number, because the mean of its divisors is an integer number (15253139118).

Almost surely, 2^61011555551 is an apocalyptic number.

61011555551 is a deficient number, since it is larger than the sum of its proper divisors (1000921).

61011555551 is an equidigital number, since it uses as much as digits as its factorization.

61011555551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1000920.

The product of its (nonzero) digits is 18750, while the sum is 35.

The spelling of 61011555551 in words is "sixty-one billion, eleven million, five hundred fifty-five thousand, five hundred fifty-one".