101216781 has 24 divisors (see below), whose sum is σ = 154365120. Its totient is φ = 63732096.

The previous prime is 101216771. The next prime is 101216789. The reversal of 101216781 is 187612101.

It is not a de Polignac number, because 101216781 - 2⁷ = 101216653 is a prime.

It is a super-2 number, since 2×101216781² = 20489673512003922, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (101216789) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 73360 + ... + 74726.

It is an arithmetic number, because the mean of its divisors is an integer number (6431880).

Almost surely, 2^101216781 is an apocalyptic number.

It is an amenable number.

101216781 is a deficient number, since it is larger than the sum of its proper divisors (53148339).

101216781 is a wasteful number, since it uses less digits than its factorization.

101216781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1825 (or 1822 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 27.

The square root of 101216781 is about 10060.6550979546. The cubic root of 101216781 is about 466.0338978945.

Adding to 101216781 its reverse (187612101), we get a palindrome (288828882).

The spelling of 101216781 in words is "one hundred one million, two hundred sixteen thousand, seven hundred eighty-one".