101006778491 has 4 divisors (see below), whose sum is σ = 101535609984. Its totient is φ = 100477947000.

The previous prime is 101006778479. The next prime is 101006778533. The reversal of 101006778491 is 194877600101.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 194877600101 = 71 ⋅2744754931.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-101006778491 is a prime.

It is a super-2 number, since 2×101006778491² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (101006778461) 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, 264415460 + ... + 264415841.

It is an arithmetic number, because the mean of its divisors is an integer number (25383902496).

Almost surely, 2^101006778491 is an apocalyptic number.

101006778491 is a deficient number, since it is larger than the sum of its proper divisors (528831493).

101006778491 is an equidigital number, since it uses as much as digits as its factorization.

101006778491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 528831492.

The product of its (nonzero) digits is 84672, while the sum is 44.

The spelling of 101006778491 in words is "one hundred one billion, six million, seven hundred seventy-eight thousand, four hundred ninety-one".