61638372251 has 8 divisors (see below), whose sum is σ = 65314116720. Its totient is φ = 57968178688.

The previous prime is 61638372247. The next prime is 61638372287. The reversal of 61638372251 is 15227383616.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 61638372251 - 2² = 61638372247 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61638374251) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1364846 + ... + 1409283.

It is an arithmetic number, because the mean of its divisors is an integer number (8164264590).

Almost surely, 2^61638372251 is an apocalyptic number.

61638372251 is a deficient number, since it is larger than the sum of its proper divisors (3675744469).

61638372251 is a wasteful number, since it uses less digits than its factorization.

61638372251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2775453.

The product of its digits is 362880, while the sum is 44.

The spelling of 61638372251 in words is "sixty-one billion, six hundred thirty-eight million, three hundred seventy-two thousand, two hundred fifty-one".