20772881 has 4 divisors (see below), whose sum is σ = 21082992. Its totient is φ = 20462772.

The previous prime is 20772877. The next prime is 20772901. The reversal of 20772881 is 18827702.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18827702 = 2 ⋅9413851.

It is a cyclic number.

It is not a de Polignac number, because 20772881 - 2² = 20772877 is a prime.

It is a super-2 number, since 2×20772881² = 863025170080322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20772811) 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, 154955 + ... + 155088.

It is an arithmetic number, because the mean of its divisors is an integer number (5270748).

Almost surely, 2^20772881 is an apocalyptic number.

It is an amenable number.

20772881 is a deficient number, since it is larger than the sum of its proper divisors (310111).

20772881 is an equidigital number, since it uses as much as digits as its factorization.

20772881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 310110.

The product of its (nonzero) digits is 12544, while the sum is 35.

The square root of 20772881 is about 4557.7276136250. The cubic root of 20772881 is about 274.8942006239.

The spelling of 20772881 in words is "twenty million, seven hundred seventy-two thousand, eight hundred eighty-one".