20977951 has 2 divisors, whose sum is σ = 20977952. Its totient is φ = 20977950.

The previous prime is 20977889. The next prime is 20977967. The reversal of 20977951 is 15977902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20977951 - 2¹⁹ = 20453663 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20977051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10488975 + 10488976.

It is an arithmetic number, because the mean of its divisors is an integer number (10488976).

Almost surely, 2^20977951 is an apocalyptic number.

20977951 is a deficient number, since it is larger than the sum of its proper divisors (1).

20977951 is an equidigital number, since it uses as much as digits as its factorization.

20977951 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 39690, while the sum is 40.

The square root of 20977951 is about 4580.1693200143. The cubic root of 20977951 is about 275.7958258577.

The spelling of 20977951 in words is "twenty million, nine hundred seventy-seven thousand, nine hundred fifty-one".