51661111654 has 4 divisors (see below), whose sum is σ = 77491667484. Its totient is φ = 25830555826.

The previous prime is 51661111651. The next prime is 51661111669. The reversal of 51661111654 is 45611116615.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51661111651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12915277912 + ... + 12915277915.

It is an arithmetic number, because the mean of its divisors is an integer number (19372916871).

Almost surely, 2^51661111654 is an apocalyptic number.

51661111654 is a deficient number, since it is larger than the sum of its proper divisors (25830555830).

51661111654 is a wasteful number, since it uses less digits than its factorization.

51661111654 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25830555829.

The product of its digits is 21600, while the sum is 37.

The spelling of 51661111654 in words is "fifty-one billion, six hundred sixty-one million, one hundred eleven thousand, six hundred fifty-four".